Does Max Units/Time links with any thing

Hi:

My question is that, does Max Unit/Time link with any thing?

I am using

Max Units/Time = 2h/d

Price/Unit  = 12/d

Default Units/Time = 8h/d

Duration = 10d

This gives me Budgeted Units = duration x Default Units/Time = 10h/d x 8d = 80h

When I assign this to activity with 10d duration the

laboure Cost comes with = Budgeted Units x Price/Unit = 80h x $12/h = $960 (for 10 days)

But where is Max Unit/Time which 2h/d ? Does this not link with any thing? Or my calculations are wrong?