Why takes time to update RCH and RCHH multiple times in a loop process in a single execution.

Hello.

I have added a single workflow, a looping process that updates RCH and RCHH multiple times in a single run.
When I did not use the data update and checked that it looped, there was no problem.
However, I executed the workflow, updated the target data to RCH using data update, then updated the workflow management data to RCH and RCHH and then looped the process..
(Only one data at a time flows to the target.)
This process had to be repeated 19 times.

(But I stopped after 9 times.)
However, it takes a very long time to process one case.
Is this a problematic process?

Thanks.