In the last 5 verses of Genesis, Joseph's 110 years is written twice. The first shows 110 years of life, while the latter shows 110 years in age. Is that just repeated for no particular reason, or are life and age two different things? The two are sometimes considered to differ by about 9 months, with life beginning at conception and age beginning at birth.
A chaism is a structure common in the Old Testament (but also found in the New Testament). It is basically text constructed in an ABCBA or ABCDCBA (or etc.) pattern. For instance, consider Luke 4
The main point that the author is trying to emphasize is generally found in the juicy center of the chiasm: in this case the emphasis is in Jesus' ministry.
It should come as no surprise at this point that I believe Gen 50:22-26 is a chiasm:
The main point, then, is Joseph's reiteration of the promise to Abraham, Isaac, and Jacob. The 110 years are repeated in order to make the chiasm more obvious.
Compare the chiasm with the text itself:
There is no reason to assume that the 9 month pregnancy period should impact the ages - either they are from conception, or they are from birth - there would be no reason to oscillate between the two.