Installing an inverter

[John Swick]

My B25 sport convertible was completely rewired acouple of years ago, including a blue seas distribution panel.
I'm installing a 400 watt invert up near the cuddy cabin bulkhead and was originally planning to get power off the main + & - supply/studs @ the fuse panel behind the helm. The supply and return cables to the panel are #2 gauge, however.
The inverter installation instructions advise to 'not route your DC cables through a DC distribution panel, battery isolator or other device that will cause additional voltage drops'.
Question: I wasn't going 'through' it, but piggy backing on the power supply.
Is this OK, or should I be running separate cables up from a battery?
Thanks in advance.