In Gameplay.constants
ResearchData
tierLabCount-0 1
tierLabCount-1 2
tierLabCount-2 3
tierLabCount-3 4
tierLabCount-4 5
tierLabCount-5 6
tierLabCount-6 7
tierLabCount-7 8
Try this. 1 lab is actually tierLabCount 0, equals 8 levels. 2 labs counts as 8, 3 as 8, 4 as... and so on.
ResearchData
tierLabCount-0 8
tierLabCount-1 8
tierLabCount-2 8
tierLabCount-3 8
tierLabCount-4 8
tierLabCount-5 8
tierLabCount-6 8
tierLabCount-7 8