All the advertisers you had on your site previously aren't likely on your site now.
CPC is based on the price that the advertisers have bid to appear on your site, and now, your adsense code is different. It will probably take time for the advertisers to find it again.
CTR could be related to the ads, since what you have now may be different advertisers than what you had before.
A new account means no history. Even if the sites have history, they will originally appear new because the account is new. New ad code, new advertisers.
A little bit like a new car. You park it in the same driveway as the old one, but unless the insurance company knows it's your car, the insurance is still covering the old car.
The ads you used before were using a different publisher ID, so even if the ad space hasn't changed, the publisher ID that was serving certain ads, isn't any more.
It will take time.
CPC is based on the price that the advertisers have bid to appear on your site, and now, your adsense code is different. It will probably take time for the advertisers to find it again.
CTR could be related to the ads, since what you have now may be different advertisers than what you had before.
A new account means no history. Even if the sites have history, they will originally appear new because the account is new. New ad code, new advertisers.
A little bit like a new car. You park it in the same driveway as the old one, but unless the insurance company knows it's your car, the insurance is still covering the old car.
The ads you used before were using a different publisher ID, so even if the ad space hasn't changed, the publisher ID that was serving certain ads, isn't any more.
It will take time.