Hello
answer to your first question: this is something secretive i cant tell in detail in public why likes drop. But in short it happens due to API abuse. the real likes all supplier deliver are from FB apps from which page is promoted and are delivered using fb API, so excessive use of that Api results in drop as FB updates after every few days and clear the likes of all such users who liked many pages via API in past few days and thus all their likes are cleared but the good thing is it does not affect the page's safety.
High quality likes are drop proof because we try our best to remain in safe limit by promoting less pages and thus they are not affected by fb updates, but since we have very limited traffic and if we use the apps for less promotion the cost goes up.
Regards
Harry
