When I was a teenager I tried to study Japanese as self taught student. The hardest part was giving a meaning to a phrase. Many times you could translate the whole phrase, but not catch the real meaning, or misunderstand it.
I have always seen the Onegaishimasu as the English "Pleae". If you turn towards a dojo mate and tell him please it can be meant by you as in "please, step on the mat", "please, train with me", "please, help me learn", "please, I am a beginner, don't hurt me too much hee hee"...and so on. I have always seen as Onegaishimasu the same way, it is in the mind of who says it the meaning hidden in it.
Same way I gave my interpretation of Doomoarigatoogozaimasuta. Even tho literally it should mean "I Thanked You", I have always meant it as "I thank you for what you just did".
Joshua, I have a question. By what you said about Onegaishimasu, is it correct to say that it has a similar meaning of Doozo?