Main value are a bit junky

[STMiki]

I noticed something weird with main stats.

Like, some item are good, but some have more or less than what they actualy have.
I came across a helmet lvl55 +15 at 1580hp, but in game, it has 1760hp

And all item have the main stat set like they are +15

Reforged stats is disabled ofc.

[almartn123]

Some event gear have weird +15 base values compared to their raid counterpart.

The optimizer I am sure uses +15 mainstats for gear when adding it automatically. It should be best to use mainstat as +15 while keeping the current substat as it is, as would influence you to +15 it in the future.
Like if a +12 gear had good enough substats for the optimizer that you would +15 for the additional substat roll.