It looks like they have taken the cap off your line altogether, or raised it well above your possible speed. Now this will be OK as long as your router can handle the changes in the noise margin, but if it can't, your connection will drop and connect at a lower speed. This is what many would prefer as it allows you to handle your own speed. The slightly higher speed you have is down to your lower noise margin. I would guess that your router has been resynced with a high noise margin which gives you the few kbs extra.
I take it your on the SVBN as only that has a 'gaming' profile...sets the line to 20Mbps down, 1.3Mbps up, delays to 8ms
ADSL Link Downstream Upstream
Connection Speed 12552 kbps 1146 kbps
Line Attenuation 32.0 db 12.3 db
Noise Margin 6.1 db 8.4 db