Ok, I agree that the pump data sheet really should be produced based on what your system needs.
however if you re-phrase this a bit and say, If I've got a pump with a BEP of 150 GPM, what are its realistic max and min flow rates, then in the total absence of real data ( the pump curve) then my finger in the wind guess is
Max flow - about 180 to 200
Min flow normally about 30% of BEP, so say 40-50 GPM
As I said - total and utter guesswork. Max flow is usually limited by end of curve / NPSH / max power of the motor issues. Min flow is the inner re-circulation which is always a bit of a vague guess, even by the vendor.
Note we often get questions here about why XYZ pump doesn't work very well and 99% of the time it's because the pump is the wrong size for the duty. So get the right pump for your duty first and foremost.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.