The district's property-tax rate already was among the highest in the region.
Cuff said the rise in retirement costs, roughly $1.6 million, is more than the $1.24 million expected from the higher taxes. Poorer districts like William Penn's, which encompasses several working-class towns in Delaware County, are the most boxed-in by higher pension bills, he said.
Every district in the state will get small rises in aid - but through targeted grant programs. That means the money can be spent only on certain things, such as kindergarten or science and technology programs, but not on others, such as teacher retirement costs.
In addition, the increased funding passed by the legislature, roughly $92 million more for traditional district schools and $8 million for charters in "Ready to Learn" grants, is divided unevenly among districts, in a complicated formula that factors in poverty and how many students are proficient in English.
Gov. Corbett has so far balked at signing the plan, as he continues to pressure lawmakers to act on pension changes and as his aides study the document for possible line items to reject. But unless Corbett vetoes the entire budget, the plan becomes law Wednesday, with or without the governor's signature, and so most district officials are working off the numbers passed this week.
In Garnet Valley, school officials weren't counting on additional money and the board recently enacted a 2014-15 budget that will raise the average property tax bill by 1.8 percent, to deal mainly with its biggest budgetary headache, increased pension costs, according to Superintendent Marc Bertrando.
"From our perspective, we couldn't really bank on how much we were going to get," said Bertrando.
The largest source of state aid for public schools, basic education funding, remained flat, with Pennsylvania taking in less tax revenue than projected and lawmakers unwilling to increase levies. The budget did contain new block-grant funding - but not at the levels proposed by Corbett.
In addition to the Ready to Learn money, the spending plan includes $100 million in the so-called Accountability Block Grant program, the same level as 2013-14.
Superintendents and district budget officers, who said that most budgets already have been approved, said that the grants will be helpful but that overall school spending will remain in a downward spiral until pension costs are reined in.
"Unfortunately, there is no magical answer at this point in time - it's a mess," said Jim Weaver, Perkiomen Valley School District business administrator.
Chester Upland receiver Joe Watkins, who earlier looked to Harrisburg to close a $23 million budget gap, now says the district will have to balance its budget on its own.
The district has already shaved half of its deficit and hopes to cut even more by the time the board adopts the spending plan on Monday, he said.
Another local district disappointed in this week's outcome is Upper Darby. It had counted on getting all the additional funds that had been proposed by Corbett. Business manager Ed Smith said the district had budgeted for $2.1 million in new Ready to Learn grant funding, but will get only $800,000.
Smith acknowledged receiving warnings that lawmakers might not pass Corbett's plan intact, but district officials were optimistic because the governor was up for reelection and because last-minute state aid had helped Upper Darby restore proposed cuts in past years. Now, he said, they might have to tap reserves or scale back plans to restore staff positions.
"To my knowledge, the only districts in Delaware County that counted on money in the budget are poorer districts," he said. "We're also the districts that have cut the most in last couple years."