Calendar Change Issue

You do not need to revise the calendar in the baseline schedule becasue the baseline schedule is is no longer used to do any more schedule calcualtions. The baseline scheduel and dates are locked down. What you need to do is to revise the calendar on the current progressed schedule to reflect 6 days per week (the schedule that wa sin effect during the time of the delay). NOT THE BASELINE SCHEDULE.

You must change the calendar to 6 days per week beyond the original baseline finish date in the schedule that was delayed.. 

If you used the updated schedule based on 6 days per week only up to the baseline finish date to do your delay analysis then the delay of 6 months that you mentioned is would we more like a 7 month delay becasue now you only have 6 available days to work instead of 7 days. This would add 1 less day of work per week or 4 days per month for 6 months this would be 24 working days or 34 calendar days. 

So extend your calendar way out past the original baseline completion date using 6 days per week and then run the calculations again to see what the new forecatsed completion date is. This should add about another 24 working days to current impacted completion date.

Yes, you should ammend the calendar

And yes, if i was the cleint, I would accept (indeed insist on!) this