I don't see the point of having an over full round.
Why? Well, let's take a simple example. The numbers themselves are irrelevant; it's the principle that matters. Assume ten houses a day, no holidays, etc.
1. You do a four week round and you have 200 customers so you're always on time. You can clean 10 houses a day and you earn £100 from them, so £500 a week for 52 weeks a year so £26,000 turnover.
2. You do a four week round but you have 400 customers so you actually get round in eight weeks. You can clean 10 houses a day and you earn £100 from them, so £500 a week for 52 weeks a year so £26,000 turnover.
I'll accept that's simplified but you get the point. In case one you're happy, your customers are happy. In case two, you're constantly under strain and apologising to all and sundry for being late. And all for no financial gain on your behalf.
Seems obvious to me.
Vin