200A Tap from an Existing 400A Tennant Breaker

[jap]

There is a retail site that has an existing spare 400 Amp Meter and Tennant Breaker in a group metering setup designated for a lease space.

This lease space only requires a 200 Amp Panelboard.

Would there be any issues utilizing the Tap Rule and installing a 200 Amp Main Breaker Panel in the Lease space with 3/0 Thhn back to the 400 Amp Tennant Breaker?

The Lease Space Panel is within 25'.

 

[A/A Fuel GTX]

I'd think that 240.21(B)(2) would allow what you describe.