Hi Fran, apologies that it took so long to get a response to your thread!
I know it's late, but just for future knowledge, people have done what you've suggested in your question.
Some people count their syns across a week so they look at having 105 over 7 days. They will then use a few each day during the week and use a few more over the weekend if they are eating out or having drinks.
As long as you are using syns and aren't going over all the time, it shouldn't have any impact on your losses, and should allow you to still enjoy being on plan