Questions about Argo Extension hose for Ulisse 13 DCI

Can this system be connected independently or must the system be filled by the refrigeration installer?

How flexible is the 4-metre extension hose? Someone here criticised it for being much tighter than the integrated hose and therefore not really suitable for temporary use. However, I only want to use the appliance with the 4 metre extension seasonally in summer and then put everything away again. Can anyone provide any information on this?

Is the extension filled with R32 refrigerant specifically?

Is the extension filled with refrigerant? And if not, wouldn't that have to be compensated with the corresponding amount of the hose?

How long is this extension 2m or 4m?