I've seen companies create "extended release" formulations of their old formulation 1 year before the patent expires to get everyone to switch over to the patented version before the generic comes out.

I've even seen it done when the previous version and the new version were still both once daily (tamsulosin, I'm looking at you!)

Yes, some insurers will hesitate to cover the new formulation when it comes out, but not all.

Sometimes the insurer will make a deal with the manufacturer so that the manufacturer is only getting paid the generic-equivalent price. But who knows what happens behind closed doors.