More so that I wonder if you set it to 7 days (is that the lowest setting?) and the model doesn't complete her 10 hours until day 9... you see what I mean?
I do see what you mean. More investigation is needed to answer this question. I wasn't busy, and it's an interesting question, so decided to look around and see if I could find any with that situation.
The lowest number you can set is 3 days. I did that and the number of New Models varied from the 60s to the 70s. I checked the profiles of several and found something.
One model apparently had started way back in April. Her profile had been last modified then and there was a post on her message wall from a member on May 2. But there she was, nearly 6 months later, broadcasting with a New Model tag.
For the member's setting of 3 days to override the 10 hours, the person who posted on her wall back in May wouldn't have actually seen her. As it was a message complimenting her on her looks, that doesn't seem likely.
So, I think in your scenario, she would still have the New Model tag until day 9. It seems this model hadn't used hers up in almost 6 months.
It looks like no matter what the member's setting, you still get 10 hours of broadcast time before the New Model tag wears off.
(more looking and found another one)