1. Your old elements were the same watts. A given element, which would be approx. 12.5 ohms, would produce 3800 watts on 208 volts, and 4500 watts on 240 volts. Many water heaters are rated at 3800/4500, and that is the deal.
2. NEVER trouble shoot a water heater by measuring from one terminal to ground.....that will lead you on a wild goose chase every time. The only measurement that matters is directly across the two terminals of the element. Either it has 240 or zero. Note that on a residential water heater, the two elements are never energized at the same time. That would pop the breaker, and the thermostats prevent that from happening.