Have you tried to run it till the light cuts out automactically? There was another customer over at MTB forum who also had his red light came on sooner with the new pack. He was advice to ignore the red light.
As near I could tell, the light heads led colors change as a result of voltage. This of course is conjunction with whatever current is being supplied. Running two lights will always change the "indicator light" values.
I believe the old batteries were 2100mA cells and the new ones are 2250mA. This equals 3Ah increase in capacity, 42 to 45, in theory about 30 minutes more run time on high, but using two lights perhaps 20 or less.
And remember, additional capacity will not raise voltage, only prolong current draw, so the "low power red" light would be on longer.
Since my first recall letter was "rejected" by the post office - it remains to be seen when and if my second will make it - probably should have sent it registered mail. Luckily I still use Dinotte. And now I can open them and replace cells as needed.