Vs – it usually means that they are proposing to change the zoning from the existing zoning of R20 to R30. That is, you are then able to potentially build more houses per hectare. Best way to find out is to check out the website for the local shire (think it may be in Shire of Gosnells?) to see their local planning drafts. To fully cover yourself you probably should write to them requesting written confirmation of their plans.

Hope this helps.