Recently I have sent my racket to be strung at 27lbs with 10% prestretch (Nanogy95) and when I collected it it was about 29.3lbs (measured with stringster app). I have been requesting prestretch on and off just for testing the difference and noticed this usually happens whenever I ask for 10% prestretch. Though one thing to note was that I collected the racket just about an hour or two after it was freshly strung... Just wondering whether this is normal? Or stringster is messing with me lol. I have another same racket with the same string but done without prestretch also at 27lbs. Been using it for about 3 weeks. stringter tells me its about 24lbs now and it does sound lower pitched than the freshly strung one.