Here is an update for you from RPI on how the status field works in ECM for documents.
Once again, PROC_STATUS is a bit field – it holds several flags encoded in a group of bits as a single number. If a particular bit is set – the corresponding number is added to the PROC_STATUS value. For example, a voucher with GL,PC,and BridgeExported flags will have a value 1+4+64=69. Obviously, when a flag is NOT set – nothing (i.e. ZERO) is added to the value. Therefore ZERO value of PROC_STATUS field means that no flags that are held in that field are set. In other words, you should not be interpreting the entire value – you should split it into individual elements first. ZERO in a bit-flag field is not a “status” of a document – it is a compound value indicating what this document IS NOT.

Example – Voucher. ZERO in proc-status means it is NOT GL, NOT AP, NOT PC, NOT sent to Corp, NOT reversed, NOT reversing, NOT exported by BRIDGE.

Proc_Status: BIT FIELD
1 – GL
2 – AP
4 – PC (purchase clearing flag – set by 8-series accounting link)
8 – sent Corp Station (set by CPROCIN/CPROCOUT – 8-series CORP tools, not used in V9)
16 – Reversed
32 – Reversing
64 – Bridge exported

Proc_Status: BIT FIELD
1 – SLIP_SOMETHING (obsolete, not used after 6-series)
2 – GL
4 – cost adjusted (set by PROCs if cost was changed by MPROCIN)
8 – Bridge exported
16 – Reversed
32 – Reversing