Is the bow marked 50 @ 28"? if it is then deduct approximately 3" x 3 lb/inch = 9# - 50 =41# at 25"
if you bow is marked at 25" then your okay.
You can try paper testing by following the directions for a PROPER ARROW at this site:
www.elitearrow.com You can use paper over an open box, or any frame resembling a picture frame set up in front of a backstop or target. It works best if your shooting level.
If the shafts are stiff they will tear left, if weak the tear will be to the right assuming your RH. Tears are from the point out.
Add weight to make the shaft seem weaker (strong) and vise versa.