I used a calculator and got the following result:



My interpretation is as follows
With 0 additional ias i am at 8 frames (3.12 attacks/sec)
With 37 or more additional ias (on body) i am at 6 frames (4.16 attacks/sec)

is this the correct interpretation?

not quite. the weapon ias (as well as off-weapon ias if you put in some number) is not featured in the resulting table! try to repeat your example with 0 weapon ias, you will get the same table
this means that you already hit the first two breakpoints, so you are at 7 frames, and 22 more ias is needed from the rest of your gear