No Magic Item Sensitivity is a -20% limitation from T67 which can be applied to Magery which removes the Magic Item Sensitivity it provides. This limitation is "built into" Power Investiture
If combined with the Total Spell Incompetence -60% limitation from T22 it creates a total of -80% similar to One-Spell Magery which reduces Magery 0 to a perk.
With both limitations the mage would have the following characteristics:
- sense changes in local mana level
Other factors apply to Magery 1+:
- Magery level as a bonus to Thaumatology skill (this should be worth 2/level as a Talent)
- Magery level as a bonus to SCILML
- aura resembling that of a mage
In this doubled case limitations like "One-Spell" or "One-College" are NOT appropriate because there's nothing a tall which pertains to spells left.
- this could be applied to NMIS because it would still limit what spells you could cast
- this could be applied to TSI because it would still limit what magic items you could sense/use
The combination of TSI with One-College and One-Spell is different though. They do NOT stack. Instead there is a different guideline:
"detect and use items but not cast spells" halves the limitations when applied to magery 0.
This is effectively using either-or enhancements but treating TSI as a -50% limitation instead of -60%. It is applying TSI as a limitation to something like Not One College +40% reducing it to +20% instead of +16%. 16-40=-24%
This is largely harmless for Magery 0 because of the lack of impact it would normally have. In the example above, -24% does not save any more points than -20% does, and there is no +4% enhancement it might allow. -40% for non-casting 1-spell-magery saves 2 points while -48% at best allows some +5% enhancement like "Reliable" if there was some situation where that could be useful (or perhaps a +25% enhancement that's -80% Limited Enhancements)