Preheat the oven to 400 degrees F.
Prick each potato all over several times with a fork. Rub the oil on the potatoes and sprinkle the skin with salt and pepper. Place the prepared potatoes on a baking sheet and bake until the potatoes are fork tender, about 45 minutes. Allow to cool on the countertop before you handle.
Lower the oven to 375 degrees F.
Meanwhile, in a large bowl, combine the scallions, garlic, onion powder, dry mustard, 4 ounces cheese, cream cheese and 1 teaspoon salt.
Slice a 1/4-inch "lid" off of each potato lengthwise. Using a spoon, scoop out the insides and leave about a 1/8-inch thick rim around the inside of the potato halves to keep them sturdy. To make things easier, slide a butter knife around the edges of the inside before scooping. Scrape the little bit of flesh still attached to the "lid" you sliced off and discard the leftover skin. Place the hollowed potatoes back on the baking sheet. Mash the potato flesh in a small bowl, and then add to the bowl with other ingredients. Mash together and slowly stir in the heavy cream. Taste and season with salt and pepper, if needed. Scoop this mixture back into the empty potato skins, sprinkle with the remaining 1 ounce cheese evenly over the tops and return the potatoes to the oven to bake until the tops are golden brown, 20 to 25 minutes. Remove and sprinkle with bacon bits, of using.
If you have a small ice cream scoop, use it to scoop the mixed potato flesh back into the hollowed potatoes. It's much easier this way.