MW Window balance part needed

A handy person from Alexandria VA says:
This is the first of two requests for window balance assistance. Balances are both from MW brand non-tilt windows. The width is 1/2". The length did not appear to match website photo dimensions since the balances were measuring 25 3/4" from end of metal to end of metal.

Additioanlly, the window sizes I believe were the same but the markings on the balances were different. One was 25DS 35 and the other was 25 9 See attached photos.

User submitted photos of a window balance.
Profile picture of Tom
Tom from SWISCO responded:
I believe we can replace these balances, yes. First, can you confirm that the nylon attachments on both are identical? If so, there's one more detail we need to see that's missing from your pictures: I would like to see the metal hook attached at the end of the cord. If the metal clips on both balances are the same, you only need to show us one, but if they're different I'd like to see both. If they are different, please indicate which clip goes to which stamped balance.

Speaking the stamps, let's confirm now whether they are the same after all. Please remove each sash and weigh them on a scale, then tell me what you get. This will allow us to confirm the exact strength needed for each balance.
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