"I look forward to any results you have."
Here, Londo, is how I calculate using a 360 day year and you can try it on your Excel (or LibreOffice or OpenOffice machine).
Place the following into a single cell: =DAYS360("1/25/1919","8/25/1922",1) with the cell formatted as Number. (you may substitute "true" for that value of 1)
That cell will return a value of 1290. However, that the Cedar Point convention didn't begin on 8/25/1922 as this formula uses. Bad news for the Watchtower apologist who is hoping that a 360 day year will redeem Watchtower's calculation accuracy.
As a different check, plug the following into a single cell: =DAYS360("1/25/1919","9/5/1922",1)
There, using both Watchtower beginning and start dates you will see a calculated value of 1300, again not the 1290 that Watchtower likes either, this time using Cedar Point's beginning date of September 5, 1922.
Here the critic might say that we're nitpicking. I say we're not the ones who've made those crazy mathematical statements. They should've known that math is unforgiving -- it either is or it isn't what you'd like it to be.
Len