In my promo series to plat

1st game get a jinx who goes 0/7 against an ezreal (???). 2nd game get the same player playing as my support while I adc. Is utter trash at thresh but I still win lane. Doesn't matter because our mid akali who "doesn't play mid" feeds their kat 5 kills in 10 minutes.

Tell me more about how promo series are an accurate measure of skill.