Ryanair Baggage Pooling

I've booked for myself and a friend flying to Biarritz with Ryanair next month. We've paid for two checked in bags- one 10kg and one 20kg.

We now realise that we should have booked two X 20kg bags instead. (Because of onward travel arrangements, we can only have a maximum of two bags).

I contacted their chat line and the agent said to just book an additional 10kg bag and, as our baggage allowance will be pooled anyway, we can just check in two X 20kg bags in the airport (rather than 1X20kg and 2X10kg).

Is this correct? We don't want to turn up at the airport and get a nasty surprise with a late check in penalty!