I realized I forgot to filter out crit hits from the max hits column. Not gonna re-upload the chart, but here's str, dex, max hit.
Code:
239 144 74
162 144 67
196 89 71
197 153 71
Seems clear to me that the max hit calculation uses str, not dex. It doesn't look like the formula Goregasmic posted fits, though. My archery skill is 238 and offense is 245, btw.