[fitzbg]

Confirmed!!!
HLR reload worked. Now I am able to voice/data roam in the Wash DC metro tunnels (red line).
So I can state that you should be able to roam using WM 6.1 with PRL 60613. No need to downgrade to 60610. I would even recommend to everybody to stay current on your PRLs. Just make sure when you call Sprint to also reload your HLR.
When you do so, remember to let them know what zip-codes you mostly roam in.
Hope this helps.