I was thinking that maybe Marcus has reached the stage where his wee is more concentrated than it used to be. If they are day toilet trained, this is when they will start waking up dry in the morning but as Marcus isn't at this stage yet, he will still wee but it'll be more concentrated, which would burn his skin, I'd imagine. I think the only way of really helping if this is the case would be to use a bum cream to put a barrier between his skin and the wee.
I hope you work out something but one disposable a night is not a big deal anyway and his comfort is the most important thing.
