FIling of S-Corp Extension with No Balance Due

I am currently working on the same and found the following (see the last sentence and for the full document use the link below) at:  

https://azdor.gov/business/corporate-income-tax/making-payments-and-filing-extensions

Filing an Extension

To file an extension on a return, corporations use Arizona Form 120EXT to apply for a maximum six-month extension to file. The completed extension form must be filed by the original due date of the return, unless the original due date falls on Saturday, Sunday, or a legal holiday. In that case, the application must be postmarked on or before the business day following such Saturday, Sunday, or legal holiday.

Please note: This is not a request for extension to pay.

The taxpayer will be liable for the extension underpayment penalty if at least 90 percent of the tax liability disclosed by the return has not been paid by the original due date of the return. For proper application of payment and to avoid delays, corporations must submit payments together with the completed Arizona Form 120EXT.

The Department will also accept a valid federal extension for the same period of time covered by the federal extension. 

If you have an expectation of a balance due, you should complete the information to pay that balance due. If you have an expectation of ZERO, then enter -1 (negative one) to indicate that. In ProConnect ZERO is not a valid number for any input, all by itself. -1 is the entry for any place you want a ZERO.