DME - Suction Catheter non-published MUE

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We have a new developmental center coming onto our DME service (we are 3rd party supplier and biller). They have 4 patients using 12 suction cathether kits per day. The LCD has no specific information on covered amounts, simply that as long as there is a covered suction pump, you can supply and bill the suction catheter kits. When I called our DMAC, Noridian customer service, the rep stated that there is no published MUE for this HCPCS code. I am expecting to be denied for overutilization at 12/day, but we have no way of actually knowing. Does anyone have experience with billing out the A4624's? I've never had difficulty in the past, but I also haven't billed more than 3 per day.

Ps. What kind of documentation should I be looking for beyond a copy of the patient's MAR? I was thinking clinical documentation of excess secretions.