airtime

Road Force machine such as the Hunter GSP9700 spins and puts pressure on the tires like it was actually on the road. This will simulate much better "real" world condition as oppose to free spinning it. Some places charge extra for this balance. Most people don't need it unless they have issues like you have experience where a "normal" balance did not fix the problem.

Lust4Lexus

Yeah- the roadforce balance machines are great. They should be the standard style of balancing machines period- why should we pay extra to have the wheels be balanced with this machine when the whole point of paying money is to have the wheels not vibrate when we drive. Doesn't make sense.

Riick

Tires may have broken / separating belts, or tire out of round.
Look at the weights, if any tire has more than 1.5 ounces of weight (as a generalization) it is suspect.
Sometimes what works is to break tire free of wheel and rotate it
180 degrees, then re-seat and re-balance.
If problem re-appears, have tire shop try the rotation.
Some parts in front end may have enough wear to be causing a problem that shows up with vibration from poor balance

Good Luck in sorting it out