Realistically, "mood" is just another term for "comfort". "Mood" would be how comfortable they are in any given environment. If you think about it, a kiss is a very vulnerable moment, and how comfortable/secure the feel would show how willing they are to kiss. So comfort(C)+attraction(A)=level of kiss(K) (I don't know calculus, so this is simplified). The "level of kiss" is judged by a mix of comfort and attraction between the two people, and ranges anywhere from a quick peck to a full on make out session. So, if the comfort and the attraction are higher, then the level of kiss will be higher. The kiss will be more intense if two people are, say, alone in a room and deeply in love with each other, than if they are just starting going out and are surrounded by people.
Comfort (C) is made of two parts: emotional comfort (C1) and physical comfort (C2). People aren't going to want to kiss if they are too cold or hot, or physically uncomfortable in any other way. So, we need to judge the closeness to preferred temperature for each person as a range of (T1+T2)/2, compared to the current temperature (CT). Emotional comfort can be calculated with P1, P2, P3, and P4 from the original equation. While attraction could be considered part of emotional comfort, it is such a major part that I decided to include it separately. It can be calculated with a base value of how much each person loves the other person (L1 and L2) averaged, plus the attraction at the current moment, which can be increased by P5 from the original equation. Attraction, if high enough, can override any other factors that are applicable.
So,
K=(C)(A)
C=C1+C2
A= P5+((L1+L2)/2)
C1= P1+P2+P3+P4
C2=((T1+T2)/2) compared to CT
The higher K is, the more intense the kiss.
If A=0, then no (consensual) kiss will occur, as the mood will never by right.
This formula is, of course, incomplete, as I don't know which aspects are the most important (aside from attraction), and I don't know the calculus to format them correctly. However, I do believe that the variable are more complete, outside of the person specific and situation specific ones (this calculation is more generalized that it could, or maybe even should, be.).