Vampire the Masquerade – Can the effects of the combo discipline Bliss stack?

The combination discipline Bliss (V20, Lore of the Clans, Dominate ••, Presence •••) is described as allowing any virtues for a willing target to be temporarily raised on a successful roll. It doesn’t appear to describe any limitations, other than the increase is “by a single dot, up to a maximum of five dots” and “Only one Virtue can be increased at a time.”

That “only one can be increased at a time” seems to imply that multiple virtues can be increased with multiple applications, but considering that this doesn’t require the expenditure of Willpower or any specific length of time, it would seem like it’s a fairly low-level combo discipline to have the actual capability of giving a target maxed out Conscience, Self-Control, and Courage in exchange for essentially just meditation on a work of art for a few minutes.

Can anyone chime in with a good reason why a Toreador with this power wouldn’t be able to compile a virtuous mix tape to listen to every evening after waking up so they can roll to max out all of their virtues?

Sidenote: I’d like to introduce an NPC into my game with this power, and I’m anticipating my players asking whether or not the effects are one-use-only or stackable. I can think of a bunch of interesting ways to house-rule this to avoid abuse (like every virtue raised after the first makes the target lose a point of Willpower), but I’m curious if there’s a rules-as-written limitation that I’m overlooking.