Right now, a 2xF32T8 equivalent LED luminaire with dimming ballast is around $400.
Not only are they much more expensive initially, the specs on best available LEDs say the output at end of life o 50,000 hours is around 70%. You can get 46,000 hours out of T8 lamps in 12+ hrs/day application and the remaining output is said to be around 90 to 95% at end of life.
The efficacy on the day its put into service is supposed to be around 73 lm/W and that's probably when installers will take readings and take photos.
I think that's pretty close to fluorescent luminaire efficacy after factoring in fixture loss. At the end of life, the efficacy will be 51 lm/W, fluorescent luminaire will maintain around 69lm/W.
70% cut off is about right for comparison against metal halide lamps, but its too low for comparing against fluorescent. I think it should be 85-90%