OTTAWA—The parliamentary budget officer says extending a pandemic measure designed to avoid layoffs at companies will cost the federal treasury almost $600 million over three years. Most of the extra spending, about $404 million, will take place in this fiscal year under the costing estimate the budget office put out today, with $174 million next year and a final $15 million the year after that. The extra spending will cover a one-year extension for provisions to make it easier to access the work-sharing program that provides an employment insurance top-up to workers who reduce their hours to avoid layoffs. The extension will mean that work-sharing arrangements at a company can last up to 76 weeks from the pre-pandemic maximum of 38, not requiring a “cooling off” period between times that companies and workers can access the program, and expanding eligibility criteria. Budget officer Yves Giroux’s report says the decision will …