Tbh I don't think there's a way you could have worded it which wouldn't sound like thinking that the DC wouldn't be spending as much time there. Which obviously they might not be, but in truth it's impossible to know, but also very hard to contemplate, especially given he's the NRP.
Reality is that even though all parents see the kids less as they grow up, even if they're out all the time they do invariably go home to their house to sleep/get washing done etc, whereas if they're only seeing their dad on a schedule it's inevitable that growing up is going to disrupt that and they won't likely come back just to sleep etc
Also, it's impossible to really know what the future holds. I am the RP, and I have suggested that once DS leaves home I will be in a position to move to be with my DP who lives three hours away from me, on the basis I had assumed that DS would probably go to a university not in London where we currently live. However, although I had said it, I was always a bit defensive when my DP has talked about it, because it feels like he is counting down that time, and i have remained open to the fact that things can change, although realistically I can't really afford to live here but do so because of DS/eXH/school etc.
However, DS has recently decided on a different career path, and the universities he would have in mind for this would all be in London. As such I now know that realistically I can't just sell up and move once he leaves to go to university because his home will always be here, and if he remains relatively local it stands to reason that he at the very least will come home on occasions. And as such my future with my DP is back on hold until .... well realistically no-one knows any more.
I think that there are so many issues with this TBH. Firstly the fact that things are happening on such a strict schedule means that there doesn't seem to be the thought of flexibility which there would be if the DC were spending time there, also the fact that it is always referred to as "contact" is, IMO, a barrier to normalising the time they spend with the NRP.
Could you suggest that the DC be more flexible with the time they spend, and have an open house type approach where their friends etc are welcome there and as such they feel it's more home and your DH feels that they're more of a permanent fixture rather than just his kids he only sees eOW?
How far from their mum do you live? Do the children need driving back and forth or could they start having more flexibility to come and go on their time/under their own steam?