an exception to that is Bank of America Merchant services. I have 2 clients with chargeback ratio above 3% for close to 5 years now, and processing volume about $1MM a month. I imagine they are simply too small of a fish for BOA to care about their CB ratio. I seen them getting accounts shut down with basically any other processor, most sensitive being Wells Fargo underwriter but somehow they remain open with BOA so maybe its worth a shot?

BOA implements First Data gateway by default these days, so most likely your previous processor is utilizing same solution as well, so less work to switch.