Can I use 2 child quick service credits for whole pizza?

[NicoleLarson]

I'm aware that you can use 2 QS credits for a whole pizza but does it only apply to 2 adults QS or I can use 2 kids credits or even a combo of the 2? I realize this doesn't give me "max value", however, feeding a family of 4 for 2 credits is worth it for us, especially if those can be child credits.