Its all about your strengths. If your standup is where you excell, then keep the ratio the same for now. But eventually you'll need to take more ground classes to make up the difference, that is unless you're a really quick learner in which case one a week might not necessarily be too little.
I'd say keep it as it is if you're comfortable that way. But if you can get into some sparring and see if you're really lacking in ground, that'll help make the decision easier.