In quilting, 1/16" multiplied over can easily become a full inch in blocks with a LOT of pieces...
I agree, all rulers can be a hair to an 1/16" off... Pick one or stay within one brand while working on a quilt. It is probably a good bet they will all be the same measurements that way :D:D:D
I have many different brands of rulers... I will pick one to measure/use for the majority of my quilt, and if need be? I can use a longer one (different brand) butted up next to the other one, slide the shorter one away and then make my cut.
You can find ways to make them all play together nicely :D:D:D