As my boss likes to say, a number is just a number until you compare it with another number. What Widgerson does here is compares numbers:

Critics, such as state Senator Luther Olsen, complain that the increase in funding for private educational vouchers is more than the increase for public schools. That is incorrect. State funding for public schools would increase by $129 million. The school voucher increase would only cost the state an additional $73 million, underscoring what a bargain the voucher program is educationally.

School choice expansion opponents are basing their claim that voucher students are getting more money on figuring the increase on a per student basis. In that sense, students receiving educational vouchers are getting more of an increase. But that's because they start at a much lower amount at $6442. Wisconsin will still be spending over $11,300 per pupil (according to the latest census figures) for public education when we are spending at a minimum 31% less per student for private school vouchers.

Widgerson's piece doesn't explain entirely the baffling reluctance some(too many) Republican Senators have on vouchers, but it's a start.