Ok that's not a problem but I'm still curious, where do you get that from?
Because when I read the part: "The longevity Ritual takes one season to develop and perform, and the subject of the ritual must be present for the whole of that season."
and the part I already quoted, the "performance" is dependant of the TeFo limit.
The LR has a cost when it's performed stated as already quoted.
Nowhere is it said the vis cost is paid twice so if it's limited by TeFo ("as a spell"), it cannot be limited by MT ("as a lab activity").
And from that previous topic (Longevity Ritual Vis Use - #45 by ArthurWynne ) I read that the MTx2 is not limited due to David Chart's comment later: Longevity Ritual Vis Use - #25 by David_Chart and this first one: Longevity Ritual Vis Use - #3 by David_Chart that the MT x2 is not limiting any way because the initial poster was using the MTx2 theory and the answer of David Chart was "keep reading" and refering to the TeFo limit later in the text, then adapting it for not only for re-performing for some one else, but also for performing one for the magus himself.
To be clear from what I read in the book and from that topic:
- you spend 1 season to develop a labtext for your self or a present person (you can add vis for potency, that vis will be added in the vis use requirement later)
- you or the person, or anyone reading the labtext can perform it (a mundane cannot missing the arts required)
- the performance is vis limited as a spell (TeFo limit, often CrCo but not always), and vis cost is age (at the time of performance) /5 round up
- the LR lasts until a crisis occurs (which is when rolling a 13 or 22+, or decrepitude score 4+ as stated in ArM5D p392 : "Characters with a Decrepitude score of 4 are extremely frail, and must roll on the Crisis Table if they undertake stressful activities, such as long journeys, or any combat. Characters with a Decrepitude score of 5 are bedridden and will die within a few months at most"), assures survival but still you are bedridden for the duration of the crisis
- you can re-perform it again