As used in WAC 392-121-500 through 392-121-545, "substantial impairment" means that after reducing the school district's or charter school's current school year basic education allocation by the amount of disallowed costs plus accrued interest the school district or charter school is likely to incur a negative unreserved general fund balance as of August 31 of the current school year and is unlikely to be able to balance the school district or charter school general fund budget for the ensuing school year without requesting the superintendent of public instruction for permission to budget receivables pursuant to WAC 392-123-060.