Light schedule question

If I am veging some plants indoors under lights, and have the light on an 18/6 schedule, and I wish to plant them outdoors within the next few weeks, what do I need to do, if it is currently getting dark at approx 9:00pm and light at approx 5:00am (making real life approx an 16/8 schedule)?

If I take the plants from the 18/6 grow room and transplant outdoors to a 16/8, will they start flowering? The daylight hours here are still increasing everyday by a couple of minutes too (I am in the Southern Hemisphere).

Do I need to gradually or suddenly reduce my lighting times to approximate real life before I transplant, or not at all?

16 hrs of daylight is enough to keep them in veg...and with the day's getting longer you'll be growing a monster...g/l

Thanks for your help! This puts my mind at ease and I can't wait to transplant outdoors!