Question re: Limited Use and Preparation Required (in Modular Ability)

[Proteus]

I'm converting an ability from an old supplement for That Other Game, but it brings up a question about how the Limited Use limitation interacts with Preparation Required limitation when using Modular Abilities.

Originally Posted by The Book of Eldritch Might

Graven Image.. The graven one can inscribe one image of an animal, beast, or magical beast on her flesh.... Inscribing this image takes 10 minutes, and it can be activated at any time afterward as a free action. When activated, the image leaps from the graven one's body and becomes a real version of that creature. It remains for one minute per level or until slain, obeying the graven one's mental commands (issued as free actions).

That seems to translate pretty clearly as:

Graven Image: Mindlink (Graven Image) [5] + Modular Ability (5 points base + 3 per point; Limited, only Allies with Minion and Summonable, -50%; Preparation Required, 10 minutes, -30%; Requires Skill Roll, vs. Artist, +0%; Social, only social advantages, +0%, Temporary Disadvantage: Distinctive Feature, tattoo, -0%) [1 point base + 0.6 points per point of abilities] + Telesend (Accessibility: only with Graven Image, -80%) [6]. 12 + 0.6 points per point of Ally advantage.

Allies would take Minion (+50%), Summonable (+100%), Limited Use (1/day, -40%), and Maximum Duration (up to 10 minutes, -50%), for a total of +60%. Assessing those modifiers after the 4x for Constant Availability, you get the following levels:

• 17 points for a 25% Ally.
• 20 points for a 50% Ally.
• 24 points for a 75% Ally.
• 32 points for a 100% Ally.
• 51 points for a 150% Ally.

Now, my question: is there something more limiting than Limited Use?

Limited Use (1/day) doesn't seem to quite fit the ability's initial description. If a "graven one" uses the ability, the image shouldn't reset after 24 hours, despite the limitation's name. In fact, if the character is imprisoned and denied access to artistic equipment, the ability will never reset.

On the other hand, the situation doesn't seem on a level with "One-Time Powers" from GURPS Supers, in that there is a way to reset the power, so vaporizing character points along with the power doesn't make sense, and a 1/5 multiplier for the whole power does seem rather munchkinish.

In the ability as built above, Preparation Required applies to the Modular Ability. Should it also apply to the Ally advantage itself contained in the slot, reducing its modifier cost from +60% to +30%, and representing the fact that, not only does the reallocation of points require preparation, so does any simple "reloading" of the initial ability?

I could see this question also applying to Vancian spell systems, which would encounter the same difficulty with Limited Use (1/day) not reflecting the fact that spell-book study is required not only to change the repertoire of spells, but also to re-enable them after their single allowed casting.

Thanks for any help that the GURPS collective can provide!