Advice on lighting times

Attached is a couple of pics of my plants 3 weeks into 12/12.
The electric company turned off all the power today for about 5 1/2 hours. The power went off just as the 250w hps was firing up, then came back on 5 1/2 hours later. Should i let it run another 6 1/2 hours to make up the 12 and then adjust the timers or should i just leave it all alone?

It does get a bit cold in the attic where they are and i wondered if having the lamp on thru the night would be better?

Nick