Hello!
I wouldn't say I'm an expert but have seen this debated a few times. Some people find that a weekly total makes SW easier to follow, in that you can have a 'splurge' then cut back for the rest of the week. In terms of weight loss, it works perfectly fine for some but not for others- it really is down to your own body.
In terms of sticking to the plan, I find it harder because, depending how many you've used, you may have to be quite restrictive in order to stay within syns for the week.
The general consensus is, if you think you can restrict afterwards to make up for it, then give it a try and see if it affects your losses in any way.
Hope that helps!