。
She didn't include the steep repair costs in the budget.
Literal
She [topic-は] high-amount 's repair-cost [object-を] budget [in-に] did-not-record.
計上する ('to record, to enter into accounts, to include in a budget') is a Sino-Japanese verb specific to bookkeeping and financial planning. 予算に計上する is a standard collocation: 'budget X in.' に here marks the destination of the entry. 高額 ('high amount, large sum') and 修理費用 ('repair costs') are both formal compounds — this is the register of business memos and financial reporting. The negative 計上しなかった (past, no record made) suggests an oversight or deliberate omission, the kind of detail that becomes significant when the unexpected expense lands.