I think you are just getting used to the feel of AH, and being more smooth on the stick.
Remember, the combat trim is only really good for getting you "close" in situations where you are changing speeds rapidly within the normaly flight envelope. What I mean is, if you are flying below say 150 or above about 450 Mph, combat trim doesn't do a very good job. In those situations, you are generally better off to use one of the auto-trim modes or manual trim. What combat trim is good at is keeping you trimmed when doing BnZ type flying where you are constantly changing speeds and hence trim-states. If you are diving to insane speed, or doing vertical maneuvers using flaps at very low speeds, combat trim will not give you the correct trim settings. Luckily it is easy to use both combat trim and manual trim. Leave combat trim on until you are in a situation where it doesn't work very well, say a very slow loop where you need lots of flap and are really slow at the top. Just hit your manual trim keys to adjust as needed for your flaps (they aren't taken into account with CT) and CT is automatically turned off. When you are out of that situation and want CT back on, simply use any of the auto-trim modes and CT gets turned on again. It works great.
What do you mean by "trim for climb"? You mean manually? Well if your plane changes speed at all, your trim condition changes. Also, as you go higher, the density of the air changes, and I'm sure that will affect your trim condition as well.
