So this type of migration isn't the same as a new connection, as in moved to a different port /line card , everything stays as is at the exchange ? I was also under the impression that the backhaul was different to be retail, i know that the peering is totally different
I can only speak for for our Be products (used for getting on 12 months or so now) but everyone i know is using Be Wholesale products, everyone has similar setup to us...ie: VLAN based (though i know Be offer VLAN and realming termination options).
The actual port/line card is not changed (downtime is about 10 mins) with the vlan handling the backhaul routes to where the termination of SPs LNS's are located. Peering as you say is different to Be Retail as ISPs have their own transit arrangements.
I'm sure there will exceptions though with companies taking from Be Wholesale in different ways, in a similar way to how BT offer various solutions.