Progressive constraints in MV-HEVC are ambiguous since PLT info not in SPS

Progressive constraints have been described in a single-layer context. In MV-HEVC, the non-base layer (nuh_layer_id != 0) doesn't have the profile_tier_level() syntax in the SPS

Therefore, the progressive constraint e.g. general_progressive_source_flag shall be set to 1 in the SPS cannot be applied to a non-base layer.

Consequently, the following statement is ambiguous:

The bitstream shall conform to the constraints specified in a dual-layer MV-HEVC decoding capability the MV-HEVC-Dual-layers-UHD420-Dec decoding capabilities as defined in clause 5.3.2 and the progressive and VUI constraints as defined in clause 4.5.3.

Shall all the layers of the bitstream be conforming to the progressive constraints? Or shall only the base layer be conforming to the progressive constraints? It seems logical that this is a bitstream-level constraint (interlaced vs progressive) but it should be clarified where in the bitstream the constraint needs to be applied.