Can/does Apple Pay combine app subscription payments ?

I just saw that I was charged 18.97 on my debit card from my Apple Pay, and it also says that on Apple Pay. It doesnt say what it is for.

In the last three or so days I have had three app subscription payments due on my Apple Pay (11.99 (29th), 2.99 (27th), 3.99 (30th)). I hadn’t been individually charged for these yet, and these all add up to 18.97.

Does Apple somehow wait until the end of the month to bill me for these rather than individually? Or some other grouping technique? Just got paranoid after seeing a purchase I didn’t do.