Finding two tape measures that agree has always been problematic IME,

Yep, it is always a problem because drop them once or twice and you
surely bend the tounge. I have a dozen tapes but try not to keep any
two of the same type. Then I just make sure I use the same tape for
the whole job. I also always calibrate my TS fence with a rule and
then when I double check my rips I can get a feel for how bad the tape
is and if it is over or under.