Not really. The question was 1-Function per key.
"key-per-function" is not the same as "1-function per key"
All calculators can be called "key-per-function but not all calculators can be called 1-function per key.
Context comes into play.
A key per function means that everytime you hit a key "some function is executed." That function does not have to be the same, to be called a "key-per-function." Context may be important. The function executed, may depend on what was pressed prior to the key being pressed.
Both the HP-67 and the HP-70 can be called "key-per-function." You press a key and something happens.
Ex: SIN executes the function to display a '4' on the HP-67 but if the 'f' is pressed first, a sine function is executed. Context may matter and still be a "key-per-function" machine.
In the question asked, only 1-functions per key was the topic. Context does not matter. No matter when you hit the key only 1-funcction is executed.
A 1-function per key means that everytime you hit the key, "the same function" is executed. Context is not important. It does not matter what occurred prior to touching the key.