Indeed, you are right. Thanks for the correction! Still the last contest demonstrated that a shorter 2.5 hours duration doesn’t really help. While a lot of people desperately think that contests duration reduction would be a good idea, as shown by the voting results here.
In fact, I think that contest duration reduction may actually make it harder for honest participants to outrun the crowd of cheaters. In my Div.2 contests, I typically landed somewhere around either rank 100-200 or rank 500+. Depending on whether I could solve more problems than cheaters (or solve the same number of problems, but faster). Not sure what’s the actual reason behind that, but cheaters tend to be somewhat “honourable” and delay submission of their plagiarized solutions until the very end of the contest. The same crowd of cheaters arriving an hour earlier with the same set of solutions would only make everything harder for us.