Chips, blinds, and betting

[JJT]

In the bar game that I play we buy 40 chips for $10, or 50 chips for $20. I guess this is considered a turbo game the way the blinds raise. By the forth level they are 8/16. Anyway, starting out with 4 (or 5) stacks of 10, as the game progresses, I re-arrange my chips by the that level to stacks of 16, but other people leave their chips in stacks of ten. So, someone will raise on the 4th level to 20 chips and I'm thinking, wait a minute, that's just 4 chips over the blind. I tried pointing that out but no one saw it, so a 20 chip raise, because they can push out 2 stacks of 10, will get people to fold, or agonize deciding to call.

Am I missing something? Or are they missing the practice of raising 2.5-3+ times the big blind?