I don't think that's how it works. Without mod_cloudflare, only the server log is seeing the same ip. But Adsense is still seeing different ips. That's why mod_cloudflare is not necessary. Am I correct?
Anyone using cloudflare without mod_cloudflare installed?
I was using cloud flare for about 6 months. The past month I noticed irrelevant ads and numerous blanks spaces. I have since disabled Cloudflare and jumped back on original nameservers. My CTR is up 300% since getting rid of this CDN