The post number for the "Feb 17 2018 02:35:54 !UW.yye1fxoQ 100"on qanonmap is #782 and on qanonposts it is #779. (On the surface, it appears that qanonmap has 3 additional posts, but without a detailed analysis we can't tell which three they may be, or if a misnumbering occured at some point in the past.)
Since I don't know the origin of the qanonmap site, I would just stick with using the new qanonposts site as the working repository for collected Q posts.
We have been directed (by notice) to use http://qanonposts.com/ from the https://qcodefag.github.io/ site as of earlier today. (And the qanonposts.com's post numbering matches the qcodefag.github.io post numbering that we all have been working with.)
Q seems to be flying at half-mast the last couple days...
The canonical post numbers are those assigned by 8chan, and those numbers vary depending on the post being placed first in greatawakening (up to post No. 100 as I type this) or qresearch (numbers up to 402,000+)
The fact that one aggregator has a different running total could come from adding a post in error, starting at different points in time, or overlooking a post. I consider both (all three?) aggregators reasonably reliable, as each provides links back to 8chan - I've yet to find those links to take me any place other than where the Q post originally appeared.
That wasn't the case for me. Before the redirection from the qcodefag.github.io site, the most recent post was numbered "780", but on the qanonposts.com site the same post was numbered "779". I'm not sure what caused the discrepancy.