Hi,
As my guess, your PSA, may have same data multiple times. in such cases it may shows more data than ECC.
At PSA, how many request you have,
Lets try to full info pack with same selections.
After that you can compare same selections data from ecc and at PSA just check latest request data only.
if your doing this task at Dev system then, just delete PSA whole data and reload selection wise.
later you can compare it it may shows same count of data.
Thanks