It’s a hack. The product that you are looking for doesn’t exist yet. So when you switch into that amp-cros program, you lose a lot of the speech-in-noise processing that you would normally benefit from because it’s the phone program. You also lose some of the high frequency amplification. There’s also limited volume/balance adjustment. If you were using a true CROS system, all the regular processing would be maintained and in the Phonak #13 size you would have more on-ear controls. Both volume control for the good ear and CROS balance control. BUT, you wouldn’t have amplification in the bad ear.
I feel like the volume issue in the good ear with the amp-cros should be able to be programmed around. If you move over to the Phonak with the #13 battery, you’ll get volume toggle and push button in the aids which would allow you to control the volume of each separately. If you made a couple of different cros-amp programs with different loudness settings you could use that for a rough sort of volume adjustment. But you will still lose a lot of the processing algorithms, which may be why you feel like the bad ear isn’t hearing as well in the cros-amp program. That’s why I initially said that you probably wouldn’t want to be using the cros-amp all the time.
So, you make a choice between two options which aren’t quite what you want.
Third possible option: I have heard of someone putting a custom product in the bad ear and ALSO wearing a CROS on that side. So you have three devices. A custom hearing aid in the bad ear, a CROS on the bad ear, and a RIC hearing aid on the other ear (or, actually, Phonak does custom CROS now, so you could go either way on the good ear). I think they ended up actually attaching the CROS to the hearing aid in the bad ear so that it was sort of one piece. It’s still not a perfect solution, but would offer modern processing for the bad ear and individual controls.
Would be interesting to see your audiogram.