I believe the prior year costs refer to costs prior to 1991-92. They do not reflect current year costs. That is where it would show up. The prior year cost refers to expenditures that were incurred prior to this current fiscal year.
Mr. Feil on Bill 15: Official Languages Act
In the Legislative Assembly on March 12th, 1992. See this statement in context.
Bill 15: Official Languages Act
Item 18: Consideration In Committee Of The Whole Of Bills And Other Matters
March 12th, 1992
Page 408
Feil
See context to find out what was said next.