Brivis A/C

I have a 18kw brivis 3 phase a/c and was looking at getting the gas checked and topped up if necessary at time of install piping is 16 mtr long and no additional gas was added. I know this is right on the limit of the brivis recommendations for not requiring top up. Has anyone has theres done and what cost was involved can you recommend a reliable company.

Melb North suburbs

Thanks Dean

What kind of gas is in it?
It should say on the outdoor unit if it's R22, R410...etc

r22

why dont you try doing a test and determine what the input air temp is versus the air coming out of the events. This will determine how efficient the a/c is. At 18kwatts the different should be around 12degrees different after 20minutes.