Anthony Vazquez/Sun-Times file photo Chicago Public Schools’ renewed three-year relationship with Aramark could be more expensive than previous agreements, the district revealed Monday as it moved to ask its board to renege on promises to dump the custodial giant. The Chicago Sun-Times reported last week that district officials were planning to award Aramark a new contract to clean CPS’ 600-plus schools just one year after vowing to move on from the company whose record includes filthy schools and inspections cheating. Ahead of that story, CPS spokeswoman Emily Bolton denied that officials had decided on a vendor for custodial services. Another company, ABM Industries Inc., had been in the running as a finalist.