When copying a command string into the Add window

you need to add up front {command}

So in your example the entry should look like this:

{command}{Tab}{Ctrl X}{Tab}{Tab}{Ctrl V}{Shift Tab}{Shift Tab}{Shift Tab}{Ctrl X}{Tab}{Tab}{Ctrl V}

When you don't use the Command button, adding manually {command}tells Instant Text that what follows is not to be considered as text.

You may also add a trailing underscore (at the end) so you won't get an extra space when expanding the entry.