Wrong. Its NOT add pay.

if you want to think of it as "add pay" because your MPG goes up, go right ahead. -and if you don't fly much that month -un used SC's do increase your paycheck. But its not add pay. if you fly a lot, unused SC's don't increase your paycheck.

if you flew zero hours and had 3 unused short calls. your MPG would increase by one hour from 73 to 74. your add pay would still say 0.0

if you flew 90 hours and had 3 unused short calls. those short calls are for free. your MPG would go up to to 74. Your line value is 90. your add pay would still say 0.0

if unused short calls were add pay (they aren't) then you would get paid 90 hours plus 1 hour of add pay (91 hours)