How to reduce LAB usage in MAX II devices?

Thank you Avatar, that was helpful.

So am i correct to say, that one LAB (containing 10 LEs) only has one set of Async Clear, Preset or Clock signal, LEs using different Async Clear, Preset or Clock signal cannot be packed into the same LAB. Am i correct?

Because i use lots of different Async signals in my design, (they're all described in schmetics) and so i see many LEs cannot be packed into others within the same LAB.