fuel tank 305 full tank

jamesj1996

hey guys so a month ago i had a little incident with my car and the majority of the bottom had to be redone. exhaust, floor, cats etc. the gas tank got dented and had to be replaced. the car wasnt driven for a month. i got it back 2 weeks ago and usually when i fill up i get about 335-345 miles full tank. ever since i got it back...full only goes up to 305 and also the miles indicator can keep dropping but the dots stay full. so im down to 265 miles but the dots still indicate a full tank. the shop said jus let the car get back to its driving cycle...for a few thousand miles then itll go back to normal...anyone experience this issue? like today i was down to 35 miles and the low fuel indicator started blinking but i had 2 dots left....2 dots with 35 miles...weird! this is my 2nd time filling up since i got it back. im getting 16.2 mpg before i was getting 18.4