Not really -
1.) most B-24 missions were in the 18,000 to 20,000 ft range.
2.) ALL medium bomber strikes were medium to low altitude
3.) most japanese bomber missions were lower than B-24 strikes
4.) the warm surface temp guaranteed higher temperatures at 20,000+ feet than ETO comparable temperatures.
5.) photo recon could remain at a lower altitude because of the incredible speed advantage the P-38 had over most japanese interceptors