Early in my ballroom dance education I ran into the dilemma of "What is right and what is wrong?". I was taking private lessons from a female instructor who taught me a specific pattern. Later I took a group class from another instructor who taught the same pattern but differently. In my in-experienced mind, I immediately thought that one instructor was right and the other wrong, but how do I decide? I struggled with this for a long time.
I finally realized that both were right, just different. Ballroom dancing evolves over time as dancers discover better ways of doing things. Sometimes it is changed to get a little different feeling in the pattern. This results in having two different variations of the same pattern. If you learned to dance or became an instructor 10 - 15 years ago and haven't kept current, there may be better way to do some things now. Don't ever be afraid to change if you feel there is a better way (not necessarily easier, but better).
This is more of a problem in non-standardized dances (W.C. Swing, Salsa, Ballroom Two Step, etc.) The standardized dances are well documented but they continue to evolve as well.
This is how I solved the problem: When you take a lesson from an instructor, you are paying for his/her knowledge and experience. Don't waste your money by ignoring the instructor because you learned it a different way somewhere else. Learn the pattern exactly as it is being taught. Only after you can dance it, can you decide which version of the pattern to use. The criteria I use is :
Notice that I didn't say "Which is easiest to dance." Short cuts are taught because it is easier to dance, but often the short cut changes the feeling of the pattern. For example in the W.C.Swing "Basic Whip" a short cut is taught for the man to step forward between the lady's legs instead of him doing a "hook step". This works and is easier for the man, but the pattern feeling changes from a "Whip" (hook Step) to a pivot (step between her legs). These are two very different feelings. Easier is not necessarily better. Sometimes there are simpler ways that still maintain the feeling.
Another example: American Style Tango, the "Promenade Flair". The man can lead this pattern by turning his body gradually and the lady gently rolls out to the point position. He can also keep his body in promenade position (without any body turn) that causes the lady to have a sudden one step swivel to the point position. At first I thought that the same pattern was taught two different ways, but actually they are two different patterns because the feeling is so different. I call these patterns "Promenade Flair Rollout" and "Promenade Flair Swivel". The exact same thing is true in W.C.Swing. For example: In the "Left Side Pass" If the man turns his body during the 1st triple (run, run, run), the lady will do a rolling type crossing step (J step, Viennese cross). If the man points down the slot, then steps into the slot on the 3rd Run, the lady will have all of her turn (swivel) on the last Run step.
In competition dancing you are trying to adhere to the set standard because that is what the judges are using. From a social stand point, I dance what "feels" the best even if it is harder to lead. Bottom line, "you" decide; not what is "right or wrong" but what are "you" going to dance. This is how you develop your own unique style of dancing.