Logic fail?

In Back to the Future Part 1, when attempting to get back to the future; Marty has to drive at 88 miles per hour and hit the wire at the precise moment the lightning hits it to get transported back.

However in Back the the Future Part 2 when the Doc is hit by lightning he is sent back in time to the part, the lightning hitting the car creating the power it needed to travel back in time. The car was however hovering and not traveling at 88 miles per hour.

As a result, wouldn’t it have been easier for Marty to have parked the car under the wire allowing it to have been struck by lightning rather than relying on needing to hit it at a precise time? Why did he need to be going at 88 miles per hour when Doc proved you didn’t need too?