Dispatcher reported confusion about whether 5G company policy allowed a CAT II approach at an airport. A previous ACARS message to flight crew indicated 5G NOTAM was in effect; but was unclear regarding CAT II approaches with AMOC approval.

Narrative

Destination showed 0 SM in ATIS while enroute. Crew informed me that they were planning to set up for a CAT II approach. At this point I rechecked all NOTAMs and saw the 5G NOTAM. I looked at the release and saw that there was a remark that ZZZ AMOC (Alternative Method of Compliance) was approved for Runway XXL. I messaged the crew to tell them that I showed we could only do CAT II on XXL. They responded 'that's what we are seeing also'. A few minutes later I decided to check the AMOC just to be sure. The latest version I had was not searchable and was alphabetical by airport name; not identifier so when I didn't see ZZZ as I expected I would because of the release remarks; I immediately emailed the duty managers and asked for a searchable document in case the airport name was different or I was missing something. I was sent an Excel document and ZZZ was not in it so I immediately sent a message to the crew that the remarks on the release were incorrect and we could not do a CAT II approach to any runway in ZZZ. At this time they were on final approach. They were able to land and I became curious about what their 5G uplink from Company had told them about which runways were in the AMOC. I looked in the ACARs traffic log and saw it told them 'RWY XXL 5G NOTAM IN EFFECT. SOP 5G POLICIES APPLY. RWY XXR 5G NOTAM IN EFFECT. SOP 5G POLICIES APPLY.' I referenced memo number X which told me this message meant 'All runways requested are NOT on the AMOC and FOM/SOP 5G restrictions apply'. This told me that their 5G uplink from Company matched the AMOC but the remark on the release did not. I immediately emailed the duty managers and informed the other dispatchers of the discrepancy. The CA (Captain) called me after the flight and I apologized that the automated release remark was wrong but mentioned that I saw the 5G uplink message was correct. The CA said that he thought the 5G uplink was just telling him that there WAS a 5G NOTAM not that he couldn't do a CAT II to those runways. I agreed that I found the wording of the uplink confusing too but referred him to the memo that explained the meaning of the various messages. I asked him if he ended up shooting the CAT II approach and he said he did not. I decided to file a report because the automated remark on my release was incorrect and I told the CA we were AMOC approved for that runway based on it before I verified it in the AMOC. The incorrect remark combined with the Captain's confusion about the meaning of the 5G uplink message created a situation where we nearly shot a CAT II approach to a runway that could have had 5G interference.The process we use involving release remarks to identify AMOC runways continues to fail us. I have emails showing that every time we have gotten a new AMOC the release remarks have been found to be incorrect for one or more airports. Last month this was not discovered until 20 days into the revised AMOC. On many occasions the subsequent AMOCs are removing runways; giving us further limitations to operations so it's definitely a safety concern when they are not updated. I would personally rather not have a remark on there at all than have the information be incorrect so maybe we should remove the remarks completely since our administrators cannot manage to keep them up to date. The process to needs to be fully audited; changes made to ensure compliance; and continually spot-checked.