I've run adsense for 8 years and made high 5 figures from them for many years. I fully am capable of spotting blank ads and that is not the issue.
If statcounter shows 300 clicks and adsense shows 50, one of them is severely flawed and up until recentl, it hasnt been the case. Adsense is choosing not to record them as impressions or clicks. Statcounter has been accurate for 8 years...it doesnt sunddenly lie about clicks.
I know for a fact my site gets over 100k impressions and it simply is getting more than 50+ clicks pre day.