7% seems a little high (although not impossible). Usually anything over 4% is considered amazing. Between 3% and 4% is a great average for sugar maples. Thermometers are a good guideline but unfortunately they can vary drastically from day to day and some days I need to go 10-12 degrees above boiling point of water to hit syrup. You may want to consider a hydrometer or a refractomete as this is the only way to confirm density. You will know once syrup cools it will be very runny. That said, maybe you have some exceptional trees!