Smart Field PDF pulling from Service Titan Estimates

New Contributor

I am looking for some help with finding a way to have a PDF fillable form(non service titan form) smart field line that would pull from the APPROVED estimate task line. 

Details: When we are out on a job and they need to replace furnace or AC, our techs will fill out a measurement form that we created that is a pdf fillable form. Then our tech will build a estimate that will have multiple options, then the customer will approve one of the options. I am looking to enter a smart field code where the item that customer approves model number will populate on the measurement form. 

The issues I am running into: The tech is filling out the form on one job number, then when the estimate is approved a new job number is created for the replacement, but the measurement form does not move to the new job number. Our shop needs to know which model number is going to be installed so the measurement sheet they are going off of can have the correct ductwork alterations made. 

Any advise or tips on how other business have handled this issue would be greatly appreciated.