I've created a flexi-task with four options. Approve as Requested, Approved with Modifications, Cannot Accommodate, Needs further discussion

In the task form that the responder completes to indicate their decision, I need other fields to show based on the specific decision.

IE; if it's Approved with Modifications, then I want to ask what modifications they need, etc. 

I have a rule in place, for the single line text field asking "what modifications are needed"

when:

Decision!="Approved with Modifications" 

Hide

This hides it but does not then unhide it when "Approved with Modifications" is selected.

I believe it is because the "decision" isn't formally logged until pressing "save" and reporting back to the task, but I cannot figure out a workaround and don't want to fire off a second form. 

I'm in Nintex 2016 which doesn't have the "save and continue" button option, nor does it have the dropdown options in rule types for formatting, etc. 

Based on other articles read, I have tried this in preview and in production, and it's not working in either mode. 

Thanks!