Short answer is no, don't overthink it. On the day you rebalance, you want your target asset allocation to be correct (e.g., 75/25).
Personally, when I make contributions, I do it so that my ending asset allocation is correct (if possible). In other words, I'll tend to buy more of a lagging asset and less of a leading asset. If you are making frequent contributions, this is similar to constant rebalancing.
However, there are arguments for other approaches, which I won't explain in detal. For example, if you want to capture momentum.