"Do hotels usually lower their prices during renovations?"

Unfortunately, the answer is going to be both "yes" and "no". How hotels handle renovations will depend on leadership and the owner. I don't think any major hotel brand has set guidelines related to renovations that must be followed by individual hotels.

I worked in two hotels under a collection of General Managers. The two best GMs happened to be at the very start of my career. Both of those men were guest-focused. As such, they would treat guests fairly under the belief that doing such would result in guests that returned. Just as important was the fact that our owners (the corporate office) held the same belief. When we renovated while I was there, we did discount rates.

The last hotel I worked had the opposite mindset. Both the GM and owners (a small local real estate firm) thought that we should get the most revenue possible. I happened to be the Night Manager there during the soft opening. It was a nightmare because we were charging top dollar for rooms in a hotel that wasn't ready for prime time.

So, in my view, the OP's question is not easily answered. It's also very difficult to tell if the hotel is question is discounting rates. As 3Cforme notes, you really need more data. It's possible that the high rates seen during the renovation might actually be discounted from what the hotel would normally charge.