Is a standard 30 day month implied in Genesis 7 & 8 ?
Or is the beginning or end of the time of the counting being factored into the total with the lunations?
In other words, Gen 7:11 says: In the six hundredth year of Noah's life, in the second month, the seventeenth day of the month, the same day were all the fountains of the great deep broken up, and the windows of heaven were opened.
And in ending in Gen 8:3-4 it says: And the waters returned from off the earth continually: and after the end of the hundred and fifty days the waters were abated. And the ark rested in the seventh month, on the seventeenth day of the month, upon the mountains of Ararat.
The time from 2-17 till 7-17 counts day 17 twice, this means IF the 150 day count is from 2-17 to 7-17 the lunation period could be 149 days with counting the day 17 of both months to make 150 days.
Example: (Remembering this is a month starting on day 17 of the month): month 2 has 30 days, month 3 has 30 days, month 4 has 29 days, month 5 has 30 days and month 6 has 30 days arriving at 7-16 + the 17th = 150 days
The 5 month of 30 day lunations has been assessed by various investigators, but only 4 consecutive monthly lunations are suggested as possible by experts, nevertheless, the model I had listed above is definitely possible.
The lunar cycle as evidently used by Israel, is especially evident in the many places where the LXX translated the Hebrew word חדשׁ -cHoDeSh to νουμηνία - nou-menia, that is literally New Moon, you can't solarize it. See LXX Greek besides the Hebrew in Exodus 40:17 and Numbers 10:10 for some examples.
The lunar cycle has no set amount of days per year by observation, it can have only a 29 or 30 day month, this means that at certain times multiple months will have 29 days in a row and multiple months at times will have 30 day, as well they will interchange 29 then a 30 and so on., Thus, the number of 354 is an average and not absolute.
However, while biblical months are lunar, the Biblical Calendar Year is only conveyed as Agricultural :
Exodus 12:2 This month shall be unto you the beginning of months: it shall be the first month of the year to you.
Deuteronomy 16:1 Observe the month of Abib- אביב and keep the passover unto the LORD thy God: for in the month of Abib the LORD thy God brought thee forth out of Egypt by night.
Thus, it is the law of necessity that requires a 13 month epact about every 3 years in order to allow Abib, meaning barley in the ear, as seen in Exo 9:31 where the barley is here called Abib- אביב, to occur in the Month of Abib.