First of all, unless you live in the north pole, nothing will happen to your car with 10/30 or even 10/40 oil, so don't worry. The 'recommended' 5/30 is mostly due to fuel economy/emissions reasons, but you're talking fractions of a percent, IMHO. I noticed owner's manual doesn't list alternative viscosities anymore; new EPA regulations, I guess.
As far as the indicator, no car that I know has an oil-life sensor, so all is based on mileage and an algorithm for harder use, etc., so it needs to be reset every time you change the oil. Since I change the oil a lot sooner than the stupid computer would tell me, I don't reset it on my cars until it pops up, just like in your case. I also go 5K miles on fully synthetic oil myself. Take care.