Either way....unless the child is with each parent equally (50/50) AND both parents have the same approximate income, then CS would be ordered.
Joint physical simply means both parents have the child with them part of the time...it doesn't necessarily mean 50/50. It could be 20/80, and it's still a share...just not an equal one. Joint legal simply means that both parents have a legal interest in things that affect the child...such as education, medical, religion, etc.
The determination of support is based upon your state. You share joint legal custody, but that has nothing to do with support. Not all states take parenting time into consideration when determining the support. Also, is the time with the child documented in the court orders? For example, if the orders say EOW, but in actuality your H has the child 50/50, then he doesn't legally have the children 50/50.....on paper.