Flight Crew Air Transport Pilot (ATP)
Confusion; Situational Awareness
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented
Procedure; Human Factors
There was no event; but an inquiry for a confusing PDC. We were filed to ZZZ at 8000 via the HAALO 2 departure. The PDC modified the routing to ATL 9 DEPARTURE.  The filed altitude showed 8000 but in the lower part of the PDC (local option fields) the instruction was 'MAINTAIN 10000FT'. While at the gate setting up the airplane; I contacted ATL clearance and asked for clarification. I knew the ATL 9 said maintain 10000 or lower requested altitude but the instruction in the PDC was not 'CLIMB VIA SID' as it had been typically until about 2 weeks prior; but was instead 'MAINTAIN 10000'. The controller said climbing to 10000 would be a pilot deviation; which had happened recently. Our initial and final altitude was clarified to be 8000. Threats include:1) Filing below 10000 creates an odd situation for initial altitude and I believe it also causes the change from the RNAV SID to the ATL 9 vector SID. 2) The recent change from 'CLIMB VIA SID' in the ATL PDCs to 'MAINTAIN 10000' looks like a solid local clearance to 10000; seeming to override the altitude instructions which are actually found in the 'routing' part of the ATL 9 SID.3) Flying at 8000 to the southwest off runway 27R results in crossing under RNAV departure aircraft who are climbing to 10000 and turning crosswind and downwind thus creating a wake turbulence threat.I contacted our dispatcher and asked about the filing at 8000. They said the software defaults to 8000 and it takes manipulation to make it 10000 for flight planning; but to avoid the confusion they could pass the word to the manager to have these flights planned at 10000.ATC consideration: If the routing instructions altitude allowance is still in effect in the ATL vector SID; without climb via SID instructions as it has historically been the case; and the lower filed altitude is required; the PDC should not say 'MAINTAIN 10000' as it does for all the RNAV SIDs. Even if this is ok legally/technically; why risk the confusion? I clarified but good chance not everyone will.
CRJ-200 Captain reported some confusion when he received a PDC in ATL that seemed to indicate a clearance to 10;000 ft; but was really a clearance to 8;000 ft.