If you didn’t have another dog how long would you leave the breakfast down before taking it away?
You know how long it is usual for her to clear it up. Personally I'd not leave it much longer than that. At 10 months old growth has slowed so it's not like she's a baby and needs the food to sustain the fast growth. So missing a meal or two wont harm her.
A word of caution, if you are in any way worried, any thoughts in your mind that things are not right, then your vet is the place to go. Remember, I cant see her so I'm taking generally rather than specifically. I'd never forgive myself if I said "All's well." and anything serious happened. And this is always a risk when giving advice on a forum like this. Many times over the years I've looked at my dogs, and had that deep down feeling that all was not well. Little things you cant really put your finger on. Little changes in behaviour, a gut feeling more than anything. We know our own dog better than anyone else so we see things anyone else would miss. I'm sure in the years to come you will develop this, almost 6th sense.