If macros were created to only operate within a specific application, would the Execute An AppleScript action be sufficient? For example,
say "Control D"
Yes, that image shows Control-D being simulated when Control-D is pressed, but that's to ensure the standard command for that shortcut is executed. And saying the command with AppleScript is almost certainly slower than with VoiceOver but maybe it's fast enough.
The next one will announce the value of the variable you want. If you have not changed the name of the variable that Peter suggested in the other thread you just have to insert this action in your Increase and decrease macros to make it work.