Attack Speed Discrepancies Between In-game and PoB

As I was min-maxing the attack speed on my cospri build I noticed discrepancy between the PoB attack rate and the in-game tooltip.

using https://pastebin.com/x9iiZG8W as build reference:

PoB says 6.44 attack rate, however in-game it says 6.45, slightly higher than PoB
If you add the 5% attack speed jewel Cataclysm Shrine into the empty socket PoB says 6.72 while in-game says 6.71, slightly lower this time
Finally if you turn on elusive for the 15% attack speed, PoB says 7.53, which is perfectly just under cospri's 7.57 breakpoints, however in-game it says 7.58, this time higher than PoB and also above the breakpoint.

Obviously it is 7.58 unless something is going horribly wrong with the in-game tooltip but bouncing back and forth between which one is higher is a bit puzzling.

Start by reproducing the three attack-rate comparisons from the linked Pastebin build: the base Cospri setup, the Cataclysm Shrine jewel, and Elusive's 15% attack speed. Trace the attack-rate calculation used by PoB and compare its rounding or breakpoint handling with the in-game tooltip; done means the discrepancy is explained and the displayed rate is corrected or confirmed.