I have to amend 3 years of returns for a client becasue they did not inform me they started collecting social security.  As a result, they owe for each year, they also owe for 2025.  They want to set up a payment plan. 

What is the best way to go about this?  Submit 2025 along with all 3 amended returns at once,wait for them all to be processed and then have the client request the plan or submit 2025, request the plan for 2025 and then submit the amended returns and revise the plan?  Am I overthinking, does it matter?