60mm f/2.8D micro lens - accessing f/2.8 on close subjects

I purchased a used but in excellent condition 60mm micro a few months ago and I've noticed that it does something that my other lenses do not. In either manual or aperture mode I can adjust the f to 2.8 as long as the focus subject is a fair distance away. However if I focus on a close subject the lens will automatically stop down a half of stop to 3.2 and will not open back up to 2.8. I have tried focusing on a point distant enough to allow me to access f=2.8 and then quickly turning the camera towards a close subject and it still jumps to 3.2. Does this have something to do with the actual macro lens and the focal length when focusing on a close-up subject or is there something funky going on with my lens?

There is a funny little red switch just above the aperture ring that I have no clue what it does but regardless whether the switch is up or down the same f-stop distant vs. close change up occurs. Does anyone know what that funky little red switch above the aperture ring is for?

Dont worry ! This is normal for macro lenses.
In efect, you are gaining close focus ability with in built etension ring. The lens group is moved forward away
from the sensor, allowing macro focus. I think you will find the red switch locks the focus distance.
When you turn this on, it helps the lens focus more quickly. It stops the lens from searching needlessly
throughout the full focus range. A lens with a short focus path will focus far more quickly.

Cool, I was wondering if it might be something on those lines. But the little red switch is not the focus limit switch, that is on the side of the lens and has the settings marked "Full" and "limit", no this switch is right above the aperture ring with a painted red bar across it and reminds me of a safety switch on a rifle. I wonder if I can download the manual from Nikon. I should since it's still an in production lens.

PS... You wont miss or need F2.8 when in macro mode. Depth of feild is extremely shallow.
While the red button is engaged, it should act as a normal F2.8 lens, but stops the lens from going into macro.
So basicly... keep the red button locked until you actualy need the macro facility.

haha lol... of course. Thats the aprature lock to prevent accidental movement of the ring !
This genraly locks off at the smallest aprature. IE F16 or 22 etc.
Keep this locked !

Interesting, thanks. But at the risk of sounding like an idiot, what exactly do you mean when you say the lens going into macro mode? Or maybe a better question would be when is it acting like a macro lens and when is it not? I guess I don't really understand the differences between macro and non-macro and have always thought of a macro lens as one that will focus on extremely close subjects.

The term macro is used for lenses designed for shooting 1/1. This means that it will shoot life size images.
IE... If you shoot a butterfly say, and the butterfly was an inch long it will appear an inch long on your sensor.
Greater magnification than 1 to 1 is called micro.
Your lens is considerd going into macro at the point where the elements start to move forward.
You can consider it as close focus when its focussed as close as it will go, while macro is locked.
You are then in macro mode, when its not locked and you can exceed the normal close focus distance.

Don't forget DOF also varies the closer you are to the subject. This means the lens can move from 2.8 to 4 if you shoot the same flower from 20 inch to 10 inch. That's why most macro use higher f stops and a tripod.