sonotube dimensional annoyances

I’ve bought some sonotube’s lately. Not branded “sonotube”, likely cheap rip offs, i got 8” versions from both rona and home depot. The ones from rona are actually smaller than 8“‘s, would probably make a 7.5” concrete form. The ones from home depot are a little bigger than 8”, likely to make and exactly 8” concrete form. Am i the only one bringing a tape measure to these places to pick stuff out cause whatever dimensions are printed on whatever are not to be trusted??

While not the most exciting thing to happen to me lately, i thought it was worth mentioning. Its been a great summer, but now its time to build!!! I’m building a balcony in my backyard, i’m all permit ready, and now i have to dig 6 feet into the ground in 2 places. This isn’t going to be pretty.