unclear about 6.5 supported topology

I was looking at kb2147672 (supported and deprecated 6.5 topologies) and I'm still not certain if my existing 6.0 topology is supported or if I need to add additional PSCs and load-balance them.

Everything is using the VCSA (4 total)

- single SSO domain

- two SSO sites in linked mode: site1 (PSC, vCenter) <-> site2 (PSC, vCenter)

I'm in the preliminary stages of planning an upgrade and found the document unclear.

Thanks