The PSkmail servers only use CALL de CALL when confirming messages or user beaons... If you have captured PSK250 then it will probably have been US servers, or Intermar maritime servers on 10148.0 (center freq) (DK4XI-30), as on 10147.0 we use PSK500R as default.
As soon as a connection is established, RSID is only used for the mode change protocol, and a lot of users don't use the software supporting the new protocol yet... Rein PA0R Rein et al. I scanned 10147 and 18105 today for six hours, alternating every 90 seconds with a 3 Khz range. I only picked up three PSk250 RS IDs on 30M and NONE on 17M. Each RS ID on 30M was not decoded well enough to produce a callsign. Since Muktipsk looks for a "de ****** " string, perhaps the stations were sending PSKMAIL IDs without a "de" ? For the last hour , I listening for 30 minutes on each frequency, listened with my own ears. I heard no PSK250 on 18105 . On 30M I heard two RS IDs and several PSK250 signals without RS ID. perhaps not all PSK mail servers are using RS ID yet ? Andy K3UK