If you calculate the schedule updates, then calculate backwards only, you overcome this OOS distortion. It's against the rules in most contracts for monthly deliverables, but in your owner weekly schedule meetings it gives a better completion and float look. You can also resequence the work as long as you are not pushing out completion. Get the new plan from the PM, model it with the owner and ask if the changes require a resubmission or just a notification in the Monthly Schedule Narrative. Typically a good owner schedule agent will accept the notification. "I'm onboard. It's just schedule maintenance. Send me a summary email for my records and I will reply that this is as agreed. Note our work today cleaning it up in this month's Narrative and we're good. Start using this schedule today and note that in the email."