Couple things about the way my solar charge controller works - likely similar for this case.
First, in float (assuming a smart charger), the controller wants to maintain the float voltage (my solar charger is set to 13.8 volts for this). The charger will simply supply whatever current is needed to maintain that voltage of 13.8. Once in float, the current required has many variables including how large is the battery bank, temperature, leakage likely dependent on age etc. Likely how long you have been in float also is a variable. The controller is just trying to keep the voltage constant so trying to compare what current is needed to maintain that voltage between boat systems with all of the variables is not really conclusive of anything.
Also, once my solar charge controller gets into the float stage where it is trying to maintain 13.8 volts it will just stay in float. However, if a load is put on the system that drops the battery voltage to under 13.2 volts for at least a minute, a new charge cycle is initiated. In float, the charger is simply trying to maintain 13.8 volts so if the charger has enough current capability to supply any loads, the charger current will still keep the voltage at 13.8 and also supply the load current.
But if the load current exceeds what the charger can put out, the battery voltage could drop down below the set point to start a new cycle (13.2 in my case) if the voltage stays below that voltage for at least one minute. I have a electric fridge running off solar and will have this happen if the solar output drops later in the day from clouds and doesnt supply enough current to run the fridge. Solar controller will start a new fresh charging cycle.
For the OP case, I dont know how much current that charger will put out or what the loads are on the boat but the above "could" be a reason for seeing the charger switch from float to charge.
FYI, most solar charge controllers repeat the charge cycle every day..
