In my observation BID stacking is a reflection to indicate how quickly the next ASK set of MMs will go.
If the "trend" is UP, then it will be that much more harder to get a fill at the BID. It does happen, but you got to remember that if you have a HUGE position on the BID and want that completely filled, then someone is going to have to sell you that amount (in most cases).
If you wish to see a run start or continue, then it is better to buy at the ASK.
Then again, this is all just my own personal opinion.
Any profit is good! I encourage you to ALWAYS do your own chart DD before making any consideration to buy or sell. My calls are just that, my call.