I removed the carpet from the second floor and I noticed that I had termite issues. After replacing the bad plywood subfloor with a new one and I've noticed that it's slightly thicker than the old one. The new one is 3/4" and it's less than 1/4" thicker than the old one, do I need to level it? I'm planning to get hardwood floors nailed down. Also, would the old subfloor, 5/8", be enough for hardwood flooring?