There's no point to setting them any higher than the water temp you need. By cranking them up to 130F the flow through the tankless is forced to be lower in order to get non-scalding water at the tap. At minimum-flow/minimum-fire the temperature regulation of any tankless is pretty flaky. In the shower the HW flow is high enough that it's probably in the better-regulating flow rate region. At very low flow the ignition delay can be longer too, and it takes longer for the water to get from the HW heater to the sink.
The solution is to crank the programmed temp back to 115F (maybe even 110F.) You never need more than 107F or so at the showerhead, or 112F out of the faucet for a scalding hot bath. Many just set the tankless to whatever it needs to be to fill the tub at a reasonable temperature with the mixer cranked all the way hot, and that's a pretty reasonable approach, most of the time.