Hi,
I agree with josnah, have to bargain abit with the ID. for me, i felt my ID charged too high, $35 per point plus additional $10 for installation each. I have 33 lighting points.
It does not matter how many switch you have per box, though mine charged me $30 or each dimmer.
In the end, i only got my ID to install another 4 lighting points on top of the 7 HDB already gave. Me and hubby looped these points to additional 22 lighting points, bought and installed the lights ourselves. Paid $8 each for 2 dimmers and wired it ourselves.
Only spent about $400 on electrical, telephone and powerpoints.