Well, I'll try not to spread my angst against miracle grow, but a feeding around the repotting time might not be needed. The new soil should have nutrients. Rosemary doesn't need really fertile soil.

I haven't fertilized my rosemary in years and it's doing fine. Mine is in the ground, in an old raised bed, but not in rich soil. Probably the only fertilizer it gets are dead leaves or the stray grass clipping that falls on it once in a while.

I can't answer for a plant in a pot. I keep mine in the ground, in semi-poor soil, and am very careful NOT to fertilize or water. They seem to prefer this.

I think it depends if your rosemary is in the ground or in a pot. I have herbs (including rosemary) in pots in fast draining mix that doesnt have a lot of organic content. I used liquid organic ferts with low numbers (2-3-1, 3-1.5-2) every other week during the growing season. Also added some 5-5-5 organic granular fert to the potting mix. Seemed to work pretty well. In the ground they probably dont need fertilizing but most container mixes dont have much nutritional value, and need a little something.