This is a really interesting question because I’ve heard both sides argued by people who really know their stuff. Personally, I eat slightly more on workout days just because that makes sense to me.
Be careful that you aren’t over estimating your workouts. 600-700 cals isn’t impossible, but it is quite high.
I would just because your body needs more proteins and carbs to regenerate muscle. It may depend on what workouts you’re doing. If you’re doing only cardio I’d say it’s safe not to eat the extra calories, however if your doing more intense weight training or HIIT training it would be a good I deal to add an extra protein shake or small meal.