Issue with new Rate Table assignment to Plan elements

When a new version of the rate table is being assigned to the various plan elements, for majority of them it takes a lot of time for the activity to complete.

We don't see any issues with the rate table creation.

We have 22 Plan elements. For one of the Plan elements, it takes around 3 Hours for the activity to complete. For majority of the other plan elements it takes 10 -15 minutes.

A year back, the plan element which takes 3 hours used to complete in 1 hour and rest of the them used to be over by 3 - 5 minutes.

We had 5 new versions of rate table created over the last one year. We have have been observing the gradual increase in the time for the Rate Table assignment activity to complete.