No, it won't hurt to give her an increased dosage of miconazole to see it it will make a difference. I'm honestly at a loss as to what this could be, other than perhaps a blockage down lower. If that's the case, coconut oil would also help.
When a sour crop fails to improve with treatment, I increase the dosage and frequency. I use the cream since it's more economical and it's easy to increase if needed. You may give up to a teaspoon of miconazole and increase frequency to three times a day instead of just twice a day. It must be...