The "reasonable" daycare costs are not automatically ordered. You need to check your court orders first for the exact terms of your obligations.
“Reasonable” is open to definition, and this is usually determined by whatever the judge is persuaded to deem reasonable. You make a fairly good argument for “unreasonable” as to the supplemental baby-sitting. However, you really should speak with an attorney about how to approach this issue. I know you want to support your child but that support should be reasonable and not excessive and indulgent of mom, even if you have a good salary.
Best of luck to you.
This response is intended to be a general statement of law, should not be relied upon as legal advice and does not create an attorney/client relationship.