Australia US tax treaty Code (18) (1) - Pro series says it's incorrect

[DTNY07]

Pro Series is not accepting Australia US tax treaty Code (18) (1)

Client moved back to Australia from the  US 5 years ago (was doing her taxes when she was in the US, about 10 years total)

She now took out her prior 401 (K) as she is over 59 1/2.  

Pro Series is saying the only Australia US tax treaty codes it accepts are 14, 15,17, 19, 20 

I have been filing a Form 8833 for her every year since moved back to Australia

I am far from an expert on this. But It seems the correct Code is 18 (1) for pension/ 401 K

I would like to avoid mailing this in, but if that is what has to be done...........

Or I am wrong with the code.  19 also has to do with pensions, but that doesn't seem correct in this case

Thanks in advance for any help on this