As a Florida child support lawyer and a Florida child custody attorney, I deal with the percentages of overnights that a parent may spend with their child and how that effects Florida child support laws. The old law used to be that if a non majority time-sharing parent had 40% or more overnights with the child then the child support obligation for that parent would be reduced. Thus, this would lead to one parent fighting for more time with the child and the other parent fighting not to allow it. The true fight was over the money. Now, as of January 2011, the new Florida child support law states that if the non-majority time-sharing parent has 20% or more of the overnights with the child then that will qualify for an alternate child support calculation. The alternate child support calculation is called “Substantial Time Sharing”. Please contact a Florida child support attorney to correctly calculate the amount of support that the alternate support calculation may trigger.