Comparing dates in process

Hi

I want to send a notification to a case owner and an escalation manager when a case has not been updated in 48 hours.

For this I found in the admin guide a reference to performing a pipeline condition (https://academy.creatio.com/docs/7-18/user/bpm_tools/business_process_setup/formulas/process_formulas) and used this to create the following condition:

(decimal)RoundOff(([#System variable.Current Time and Date#]-[#Read modified time.First item of resulting collection.Modified on#]).TotalHours) > 48

However, when trying to save I get the following error - Formula value error: Invalid Operator. I cannot see why this is the case, as it follows the guide exactly with just the variable values updated.

thanks in advance

Mark