Service Charge/ Gratuity age of child vs. adult

Hi,

I'm going on my first cruise, and just trying to calculate and prepare for some of the on board costs. I'm travelling with 3 teenagers, ages 12, 15 and 17. On the ticket it says child, but some service charge sites say that you pay for an adult after 12 years. Can anybody confirm what is correct on the MSC Seaside?

Thanks, :)

My 12 and 17 year old were charged $12.50 a day, same as adults. My 2 year old was charged $6.25.

2-11 they charge $6.25 and 12 and older it's $12.50

And luckily my 1.5 year old will have $0 in daily service charges.

In reality, the reduced price for our 2, 7 and 11 year old were another tipping point for cruising MSC instead of our normal go-to, Carnival.