interpretation HB average utilities

Dear Sawtooth Software Team,

I have a few questions regarding the interpretation of CBC HB part-worth utilities for my master thesis.

1)  a negative average utility value DOES NOT say that the level is providing negative utility. Correct?
For example: An attribute has 4 levels. Utilities of level A and B have a negative sign. But that does not mean that A and B is disliked, right? We can not interpret the sign.

2) Can I report at which rate utility is increasing between levels? For example: Change from level A to B is 70. From B to C is 30. From C to D is 12. Can I state: Further increasing attribute X is still adding utility but the at a lower rate?

3)
Can I interpret the utility differences between levels?
For example, one level is regarded more negative than another since there is a utility difference of xy.
Suppose there is level A, B and C. Utility increase between A and B is very low / their utilities are similar. But utility increase from B to C is high. Can I then say that compared to level C, A & B are rather disliked?  Also, can I say: utility increase is highest when increasing B to C?

4) Also, when I compare groups of people (e.g. demographics): Is it correct to say something like: Men drive more benefit out of level xy (∆U=7; p<0.05)? (For these comparisons I use the zero centered individual utilities and compare means via t-test)
related to an answer for: estimated utilities