Yeah, you're unnecessarily doubling the penalty.
The regulation requires correction to the Landing Distance Available (LDA), not the Landing Distance Required (LDR). LDA is the length of the runway, LDR is the distance it will take the aircraft to stop.
Think of it like this - you have to prove you can stop on the runway if the runway was shortened to 60% of its total length.
So:
Corrected LDA = 3,000m * 0.6 = 1,800m.
LDR = 1,200m
You're good to go as you have a spare 600m over what is required to stop the aircraft.