If I understand the issue correctly, SendKeys literally just sends
keystrokes to the active window. Access cannot determine if the application
in the active window is in a state to receive the keystrokes - like typing
keystrokes on your keyboard, but with the monitor off. Its not a scenario
that MS has control over as every software company out there would have to
build into their application code that confirms the application state.
I would suggest that you're love of SendKeys is only because you're in the
very small minority of persons that's never had adverse problems with it. In
short, you've gotten lucky, but statistically you're headed for a train
wreck.
MS, and many other application developers, do provide a viable means for
working with an application from within another - Automation. It is simply
the ability to access the Object Model of one application from within
another. You've most likely seen posts and code wherein one Office
application uses another to perform an action - such as Access automating
Outlook to generate an email or Outlook reaching out to Access to get
information from a .mdb file for use in an email.