3g Tethering on Simple Plans

Currently my family has the 5 lines for $180 unlimited + 14 gigs of tethering. We also have a government discount. Will the 512 kbps tethering also apply to our plan? Or is that only for the new plans?

Also do the new plans have the government discount? Debating if it's worth switching as one line has the need for unlimited tethering.