"In Service" might leave the IRS room to do whatever they want, but it seems to be something like, connected, powered on, and ready to use, rather than "being used" right now, or even has been used.
With some things it might mean after first use, but a rental car might be "in service" when it is ready and available to rent, not later, when it is first rented.
If your "installation" is ready for visitors that might drop by and use your Charging-Connection with their plug-in EVSE, that might mean your "dock" is "in Service", even if you do not yet own an EVSE.
This is primarily based upon my (limited) "experience" from placing my PV system "in Service".
See SOC/GID-Meter and CAN-Do Info
2011 LEAF, sold in 2015
2010 Prius, 2014 silver Tesla S
Nissan EVSE, mod to 240/120v 16A
Solar PV: 33 x 225W -> 7 kW max AC
To Sell: X-treme 5000Li EV motorcycle