In the rulebook, it says that when a lab is in use, a portion of its cost is spent on the project. And I do not understand exactly when the laboratory is considered to be used. Only when he brews potions and creates / recharges staves and wands? Or is it always when the wizard is engaged in something magical, creates a magic scroll, somehow adds spells to his spellbook?

I'm preparing an OSR campaign with home rules heavily inspired by 10footpolemic. Armed with the lotfp corebook, LL - Labyrinth Lord Advanced Edition Companion, LL - Theorems & Thaumaturgy and AD & D2 Player Handbook, I am creating an extended and sometimes reworked spelllist for MU. The question arose at the moment with Phantasmal Force. Why lotfp-PF cannot create objects and phenomena as it was possible in AD&D2, and most importantly, are there any restrictions on the capabilities of creatures created by this spell? If the magician creates his own copy, will the copy be able to use magic as the original? Will Phantasmal copy be able to shower enemies with Phantasmal Magic Missles, Phantasmal Fireballs, and so on? How will the Phantasmal Charm Person work?