Unfortunately...
This is an interesting take on the idiom, and while the KJV does translate the Hebrew of Psalm 90.10 as 'threescore years and ten', the Hebrew simply says 'seventy years' (שבעים שנה).
To understand the meaning of 'time, and times, and half a time', we really should stay within the individual context that we find the phrase, being Daniel (first of all), and the Revelation (second of all).
The idiom in Daniel
To summarize the reading of Daniel by critical scholarship (e.g. John J. Collins, Michael D. Coogan, Craig C. Hill), the apocalyptic visions of chapters 7-12 are understood as complementary recaps of each other. The 'little horn' of chapter 7 is the same as the 'little horn' of chapter 8, and the same as the 'king of the north' who is a 'contemptible person' of chapter 11.21-45, and probably also the same as the 'prince' and the 'desolator' of Daniel 9.26-27.
We find the 'time, times, and half a time' first mentioned in Daniel 7.25, where the 'little horn' persecutes the saints of Israel and attempts to abrogate the commands of the Torah.
He [the little horn] shall speak words against the Most High,
and shall wear out the saints of the Most High,
and shall think to change the times and the law;
and they shall be given into his hand
for a time, times, and half a time.
(ESV translation)
This is then recapitulated in Daniel 8.9-14, where the 'little horn' assaults 'the glorious land' (Israel), and persecutes 'the host' and 'the stars' (explained to be the 'mighty men' and 'the saints' in verse 8.24), and attempts to abrogate the sacrificial offerings of the Torah during a period of '2300 evenings and mornings'.
And again this is recapitulated in Daniel 9.26-27. Here the 'days' of the seventy 'weeks' are commonly understood as representing years. Thus the final 'week' of seven years is split in half, where in one of those halves we again see the 'desolator' attempt to abrogate the sacrificial offerings of the Torah.
Once more this is recapitulated in Daniel 11.31, where we find the same abrogation of the sacrificial offerings. No time frame is provided in the immediately surrounding text, but chapter 11 does naturally flow into chapter 12, where we find references to the abrogation of offerings, connected to the 'time, times, and half a time' (12.7), and '1290 days' (12.11), and '1335 days' (12.12).
So between all these complementary parallels, we find the following time periods:
- time, times, and half a time
- 2300 evenings and mornings
- half a 'week'
- time, times, and half a time
- 1290 days
- 1335 days
The 1290 days is 3.53 years, while the 1335 days is about 3.65 years. How the the 2300 'evenings and mornings' should be understood is disputed, though a somewhat flimsy suggestion is that it should mean 1150 evenings and 1150 mornings, i.e. 1150 days total, which would be about 3.15 years in length. And of course, we have the half a 'week', which is widely accepted to mean 3.5 years. If we allow for some leniency in rounding these numbers off, they all come close to 3.5 years.
Because the 'time, times, and half a time' idiom appears in close relation to them, or in direct parallel, it is highly probable that the originally intended meaning of the phrase is 3.5 years.
The idiom in the Revelation
The Revelation certainly borrows the idiom from Daniel (along with other imagery from Daniel's apocalyptic visions, such as the beast, the river/lake of fire, or the son of man on the clouds). But where Daniel's symbol requires a bit of (I think reasonable) fudging the numbers to round off to 3.5 years, the Revelation is nearly explicit with this.
The Revelation mentions a few time periods of X duration (ten days in 2.10; five months in 9.5, etc.), but we find an interesting set of time periods within chapters 11-13. In quick succession, the author mentions a number of months, a number of days, a different number of days, and then mentions each of those three more times. When we study their appearances, their order is actually a chiasmus:
A — 42 months (11.2)
B — 1260 days (11.3)
C — 3.5 days (11.9)
C' — 3.5 days (11.11)
B' — 1260 days (12.5)
A' — 42 months (13.5)
If we follow a simplistic model of a 360-day year and convert the units for the four outside items, then we have:
A — 3.5 years (11.2)
B — 3.5 years (11.3)
C — 3.5 days (11.9)
C' — 3.5 days (11.11)
B' — 3.5 years (12.5)
A' — 3.5 years (13.5)
While the units are different, all of the numbers equate to 3.5... and it is only within this chiasmus (though, oddly, not at its center) that the author uses the phrase 'time, times, and half a time' in a passage where it is quite evident it is meant identically to one of those 3.5 years:
a. and the woman
b. fled into the wilderness,
c. where she has a place prepared by God,
d. in which she is to be nourished for 1,260 days.
(Revelation 12.6, ESV translation)
and
a. But the woman
b. was given the two wings of the great eagle so that she might fly from the serpent into the wilderness,
c. to the place
d. where she is to be nourished for a time, and times, and half a time.
(Revelation 12.14, ESV translation)
Concluding summary
The phrase 'threescore and ten' in Psalm 90.10 is simply the KJV's translation of the Hebrew word for 'seventy'. Any connection with the 'time, times, and half a time' idiom is superficial; it only works when we work from a specific English translation.
In Daniel, the idiom 'time, times, and half a time' is to be read in parallel with the other time references, which equate 3.5 years, or may be rounded close to that.
In the Revelation, the author has clearly borrowed the idiom from Daniel, and makes it very obvious he understood and intended for the phrase to mean 3.5 years.
