Discrete uses

The discrete uses concept is mentioned on P153 as one of the criteria an Always On ability cannot have (2nd bullet).
:doesn’t have discrete “uses” built in or added via Costs Fatigue, Limited Use, Takes Recharge, etc.
Further down (under Transient) a similar phrase is used:
:specifies “uses” of finite duration
This is a "duration that the user can't control"
Some confusion is created though, as while Costs Fatigue adds discrete "uses" (which are of finite duration: 1 minute intervals) there seems to be some implication that it could operate like Switchable in the middle section:
"ongoing effects that last until the user":
#"turns them off"
#"stops concentrating"
#"stops paying FP (for advantages that normally cost FP or have Costs Fatigue or Usually On)
The question at hand is: when you pay 1 FP to turn something on, is it required to last that full minute, and only ends when you choose not to pay FP at the start of the next interval?
That is how magic spells work with "maintenance". It is "free" to end a spell by not maintaining it at the end of an interval, but otherwise costs 1 FP or using something like Counterspell.
How spells are emulated (with similar language) in Sorcery can thus be illustrative of how Costs Fatigue operates.
category:rules