The Multiplus II manual has this to say about the current limit: “adjustable current limit for PowerControl and PowerAssist functions”
There’s also a table showing “the current limit settings for which PowerControl and PowerAssist come into operation.”. For the 5K, it says “11-100 A”.
My take:
A 1 A setting seems to be out of range. It’s not clear why lower settings are allowed, or if they’re enforced. Regardless, PowerControl limits how much power is used for charging, it can’t do more than stop charging when the limit is exceeded, i.e. it doesn’t limit what other AC loads use, just how much the MPII itself uses for charging.
With PowerAssist, the AC input isn’t disconnected when the limit is exceeded - the MPII will supplement the AC input with the inverter to the extent it can in order to stay below the limit. But again, it can’t prevent a load from drawing more than the limit plus the available inverter power.
Also, see this post.