4w6d HCG question...

1st Beta: 198

2nd Beta: 349

My doctor said she was fine with the 48 hour rise even though it didn’t quite double since it went up by almost 80%. I’m not convinced. Has anyone experienced similar numbers and had a successful pregnancy? I know they say 48-72 hours so maybe I just needed some more time? I also spotted today which she was not super concerned about since it is normal during early pregnancy.