MrScrogg,

From what I gather, you already have shared residency (week on, week off schedule).  So, your question is how to modify child support for this case, correct?

Child support for shared residency has two different methods.  One method (shared expenses) is the one you are apparently wanting to use.  This is where the parents each pay for their own expenses or they reimburse each other for the expenses.  There can still be small child support payment.  The parent making more money will always be required to pay this small amount unless they agree to disregard that payment.  For the shared expense method, the court requires an expense sharing plan to be agreed and filed with the court.  So you will need to file both a worksheet and an expense sharing plan.

If the other party does not agree to share the expenses, the court will have to determine whether sharing would be better or having one parent or the other pay them.  This later method is called the Equal Parenting Time (EPT) formula.  When this is used, one parent is put in charge of ALL direct expenses.  The paying parent pays their portion of these expenses to the other parent.

If you've not yet, I would recommend using the tools at efamilytools (https://efamilytools.com) to calculate the amount.  When you're ready, you can pay the small fee and create the worksheet which can be filed with the court.  To create the expense sharing plan, I recommend you look at the Kansas child support guidelines as there is a template/example there you can use.