I'm confused

Sen. Mar Roxas wants the government to either junk or to impose a moratorium on the Exanded Valued Added Tax on oil and petroleum products in order to save Filipinos from the rising cost of fuel.

In its place, in order to fill up the gap from lost revenue, the Senator says government should instead makes its tax collection system more efficient.

But the VAT (classic or expanded) is an efficient tax collection system, is it not? So why junk an efficient system to address a problem that's beyond the government's capacity to control?