No new growth

[Ravi]

I topped off my auto flowering plant, which I have done before, two weeks back. Since then I have not seen any new growth like one typically would expect. The plant looks fine but just no new growth. The lights are still on 18/6. Do I switch the lights to 12/12. Been about 25 days since I transplanted to the big pot that you see.

[DabberDog]

Your plant shouldn't have gotten any new growth for a while. You're about to harvest.

[Ravi]

Thanks but then that's a surprise since the plant from the time I set the seed to sprout to date is only 52 days. I thought it stopped growing because I topped it

[DabberDog]

52 days (coming on 8 weeks) is a short time, but not unusual for an auto to do her thing. You can even have plants of the same strain, in the same grow, at the same time, with all the same-same everything, develop weeks apart.
All topping did for you was get rid of smokable dope. The side branches might have gotten a little bigger, but topping removes the money shot. It does not create two new mains like topping fem/photos.
Another glance at your plant, what do you mean by 'topping?' It looks to me like you cut the sides and left the main.
Another glance at your post, there is much experience around here with auto light schedule. 12/12 is what you want when you want to get your fem/photos flowering. Autos do better if you stick to 18/6. Flowering marijuana loves light. The more the better. You also never need to worry about providing darkness for autos. Open tent, closed tent, lit room, dark room. Autos will flower regardless of light and do better with more.

[Allotrope1000]

I personally believe autos can be topped around forth or fifth internode. Topping = removing the top growing point. You have to do it before flowering.
I have three experimental, topped AF plants which "bushed up" with more flower sites. To illustrate my lack of thinking this through, I forgot to plant a control plant to see how topping vs. non-topping affects yield.