I think I know what you are saying. You must mean for CATHE workouts you have reached the heaviest weight you can lift. I find that this is the same for me these days, meaning....I rarely find nowadays that I ever reach for heavier weights. Not at the rep speeds in which Cathe goes.
Like for Power Hour. I always seem to grab the same wt. and then when I TRY to go up, I end up failing and dropping back down. Same goes for many of her other workouts. I STILL drop all weight in PH after starting with 20lb. dumbells for lunges!!!
After you have been doing Cathe tapes for a long time I do feel that at some point you find that your strength plateus. Even with S&H! Yeah, I can be really strong for S&H but as soon as I go back to Power Hour, I am still doing no more than 15lbs for chest flies, which usually ends up dropping to the same ol' 12lbs!! There is no HUGE increase in strength after S&H for me. Does that make sense??
I really do think that every now and then it is essential to break away from Cathe workouts, or maybe even video workouts and really work with your own designed strength training routine. I think, for me, this is exactly why my real bench press has not ever increased. Because with Cathe workouts I barely ever load more than 45lbs on my barbell, but if I were to do 3 sets of 10 in the gym, I could probably handle 75lbs. easily. So, if you routinely stick with the same 45lbs., how do you ever expect the 75lbs you do in the gym to go up??
I have the same feelings in regards to pull ups and push ups. I SUCK at them and the reason why is because I NEVER do pull ups in a Cathe workout AND I always do a set number of push ups. I really think different training is required if you really expect to hoist your body weight. Lots of endurance work just won't cut it if you expect to exceed your personal best on these exercises. That is why you see posts here from frustrated push-upers saying they can't do them. And what is the usual response? Not "just keep doing Cathe and you will get there", but usually a more specific routine of WHAT TO DO ON YOUR OWN to acheive push up success. Cathe might help you do 5-10, but I don't know about much more.
I spend alot of my time these days frustrated with mediocre strength gains and really should break away from the videos. I find it hard though. Even though I know much about fitness and could easily design my own program, it is almost like I lose all focus when I have to do it myself. I get like this with weight training but can easily do cardio on my own. I think if I had a training partner that was as dedicated as I it would be perfect. But we all know how hard those are to come by.
As far as truly answering your question.....I would never go lighter and work back up. I think your dilemma simply means that possibly you have grown out of your current vids and need to break away to a different style right now. I think push ups and pull ups are great for increasing upper body strength but you will probably need an assisted pull up machine or someone to help you up. Or, design your own program at a slightly slower speed than Cathe and grab heavier weights. You may find that you have not "topped out" at all, but that, as Kathyrn said, you just need to enlist different rep speeds....
Good Luck and keep us posted!!
Janice