Great detective work, @Topaz.
To confirm my (layman’s) understanding, 0x4612 is used to define the operating limits of any FSV (i.e. min/default/max, as listed in the User Manual), with the measurement unit coded as a hex byte (1 = degC, 3 = min, 0 = no unit etc). (By contrast, the current FSV value is stored in other registers, such as 0x424A for FSV #1011.)
I see in the NASA codes list Samsung NASA Codes.docx (77.1 KB) that 1) 0x4612 bears the Description “Source_Address_Class: WiFiKit” whereas in the Packet Structure table, “WiFiKit” appears (packet byte 03) as 0x62. Have you resolved this apparent inconsistency?
I presume that the FSV operating limits (as defined by 0x4612) are fixed for any given heat pump model, and that any FSV change request (either from the Remote Controller, or from SNET via F1/F2) will only be honoured if it complies with the operating limits.
I believe that we have already determined the syntax of an SNET FSV change request, in Contribution: Samsung ASHP NASA link <-> MQTT bridge (Home Assistant) , post #59 onwards. Presumably an FSV change request from the Remote Controller would be similar (I haven’t tried my proxy on F3-F4 yet).