Yes I've found the UDs to be harder than the DDs esp at first. It is easy to go a bit mad on UDs, I do like to keep track on UDs (although you're not meant to worry about UDs too much) so I don't go over the top. DDs I've found easier and lately really got into the swing of them. Planning is the key, esp on DDs, I like to split it into 5 x 100 cals (or less) and not eat until at least lunchtime, then I have plenty to get me through.
Good luck x