the settings “l_rxqual_dl_h” is the threshold above which the rxqual is considered too bad, for non-amr calls, so a ho cause quality DL is triggered.
l_rxqual_dl_h_amr is the equivalent threshold for quality HO, but for amr calls only, this time. Anyway since you are working with nokia, you should check with them and open a support ticket on this issue ?
perhaps you’re seeing real ul interference ? SFH might have increased your UL interference in your network?
have you checked “idle” interference band measurements ?
i don’t recall you have to reset the bts to enable sfh. I’m almost certain it is not needed. why would you think so ?
a cell in which you change frequency or hopping mode will reset anyway : it will go down and reset itself to apply the change.