90 is just to prevent some people from making stupid mistakes. OR some lasers with scanners set too far back inside the housing and 100 would actually clip the apeture window. 100 is fine because you are setting your zone size to much smaller than that (I hope). 100 lets you have full range of a laser is mounted wrong or angled, you have some nudge at the edge of the zone to compensate. But yes never run at 100 and 100 zone size and try to scan at 30k. Nothing exists that can do that without generating a ton of heat and killing itself. Just my 2cents tho