It really doesn't matter what the turnaround times are with other LAQ!
If it's been a problem in the past, you know it may continue as such.
You like her work, and want to continue with her.
You've noted that once you called, she moved on it.
So ... when you leave it with her, you need to tell her a FIRM date you need it.
And ask if she can make the date or not?
And if she can't ... you have to be prepared to take your business elsewhere.
Otherwise, you are sending her the message that your FIRM date is NOT so.
That it's only a wishy-washy one!