When I done this mission challenge in November last year, I do not remember getting repeat credits.
This mission challenge 3-5 seems to be the only mission challenge where you can repeat and earn credits, I know it is does not give you much payout but it is still easy credits.
In 5 minutes you can get 34,200 credits as long as you get gold in the 6 times you do it. Each time you get gold do not exit to get the credits because you only waste time getting the 34,200 credits in 5 minutes, just press on retry because the credits add up each time you press on it after getting Gold, the credit still add up even if you get silver or bronze.
This mission challenge 3-5 seems to be the only mission challenge where you can repeat and earn credits, I know it is does not give you much payout but it is still easy credits.
In 5 minutes you can get 34,200 credits as long as you get gold in the 6 times you do it. Each time you get gold do not exit to get the credits because you only waste time getting the 34,200 credits in 5 minutes, just press on retry because the credits add up each time you press on it after getting Gold, the credit still add up even if you get silver or bronze.