Hey River...
It's ok to have a little under, or over for that matter... As we're not trying to lose any more, theoretically,

...but simply finding a good balance for our bodies, it's more about how we feel than strict weights... or at least, that's been my approach.
Generally the protein portion should be 1/4 of a regular sized dinner plate... and things often come in a portion size anyway. For example a chicken breast, a small pack of smoked salmon, 1 small mackerel, you get the idea...
Hope that helps hunny... and you're getting on ok with RTM so far... I'm loving it, now in my 2nd week. It's hard to know how much salad and things I should be having too, but again, am just listening to my body and not over doing it. We are in effect, creating a meal, as we add the various extras over the weeks, so it shouldn't be tiny... but not heaped either... 25g extra of salmon one day, or less the next is irrelevant really... relax and trust your instincts. I am already starting to recognise if a portion is just too big by eye, and you will too. In fact, I'm using a Diet Plate (which came highly recommended by the lovely SexyChick!) and it's great for helping with portion size! Pricey, but brilliant!
If you're not gaining (during the first couple of weeks anyway), you're doing it right...
xx