Paint Shop Pro Gif Optimiser (not)

I find it odd that Corel Paint Shop Pro X has a 'gif optimiser' option, which one would assume was designed to produce smaller filesizes than the simple 'save as .gif' option.  But it doesn't.  I just saved a file directly via 'save as .gif' and it's literally half the filesize of the 'Optimised' version, even with colour reduction and using various different methods for that.

I assume that someone built a better gif optimiser into PSP, but forgot to take the manual 'Optimiser' which has been around I think since version 5, out.

I keep forgetting about this and rediscovering it, so I note it here (on what could be called the 'Bagpuss principle') in the hope that it may be useful to someone else who happens to be wandering by.