Topeka ? Some Republicans think Democratic Gov. Kathleen Sebelius and her aides are underestimating the size of her proposal to raise taxes for schools.

Sebelius describes her proposal for higher sales, property and income taxes as a three-year, $304 million package. Some Republicans put the total at more than $600 million.

Here’s how Sebelius figures it:

The plan would provide $137 million in new funds for schools during the state’s 2005 fiscal year, which begins July 1.

In fiscal year 2006, an additional $83 million would be provided, above what was provided in fiscal 2005.

And, in fiscal 2007, an additional $84 million would be available to schools.

Those figures add to $304 million. Also, annual spending on schools would rise from $2.6 billion under the current budget to $2.9 billion in fiscal 2007.

Here’s the Republicans’ math:

Schools would receive $137 million in new money in fiscal 2005.

In fiscal 2006, they’d still receive the same $137 million, plus the additional $83 million.

That $220 million would still be in the budget for fiscal 2007, to be topped by $84 million in additional funds.

Therefore, some Republicans say, Sebelius proposed a three-year plan worth $661 million.

Others even say the package would increase taxes nearly $1.3 billion over five years.