It is almost that way. First car does get priority and will get more of the charging power, all else being equal. But, let's say the first car just plugged in and is very low on charge state. They would get something near 115kW of the 120kW from the charging equipment. Second car would only be left with 5kW. They don't let that happen. Secondary car gets 30kW minimum, so first car would start at 90kW. That's a little lowered, but it would have tapered from 115 down to 90 within the first 5-10 minutes or so anyway, so it's not that big a difference.