On my factory Cooper 22-250 (pictured above) the POI did not change, and accuracy (at 100yds) was typical (.5 MOA)
I have a custom 338 LM with a broom handle thick barrel, and POI did change on this (at 200). POI moved upward about 2.5". Accuracy was also typical for this rifle.
I guess POI changes will vary from rifle to rifle, but accuracy seems to hold. I won't be using mine for ladder tests or for LR groups, but for confirming drops, keying in pn velocity, and testing a known load for ES it is awesome.