How can I get a 1040-SR generated where necessary?

So? Let it be.

The tax is the same.

A lot of us prefer to use 1040 for all returns. That way we only have to look at one format.

If you have a client with serious vision problems, perhaps you actually do want the 1040-SR to print.  I can see I'm not the only one who doesn't like dealing with it (and even though my clients are all retired, none of them need it).  There's an override in order to print the standard 1040.  I used PTO for the first time last year and I applied it to all my clients. The override carried over from last year, so perhaps that's what you are dealing with. 

Go to General, Misc.Info./Direct Deposit, Miscellaneous tab, and scroll down to the line where the SR can be suppressed.  There's probably a 2 in the field, which you can delete or change to a 1. 

But seriously, unless your client has serious vision problems, consider not using the SR.  The only other advantages to the form apply to people who are preparing their own returns by hand!