Let's see if I can translate this.
In Jeff Foxworthy terms.
masu, as in arigato gozaimasu would be if a relative came up to you and gave you ten dollars that they owed you. You'd say, right then, "Shiiiiiiit, 'bout time ya paid me back, Cousin/Uncle/Grandfather Slim." Translated -- arigato gozaimasu. (English - Thank you for repaying me right now.)
Now, let's say that yesterday your neighbor helped you round up five cows that had strayed beyond your fence. The neighbor had something to do so you didn't get to talk to him after you put the cows back in your field. You see the neighbor the next day and say, "Hey Billy Bob, ya'll sure got me out of a pickle tha ot'er day." Translation -- arigato gozaimashita. (English - Thank you for helping me yesterday)
Here is an example commonly used in day-to-day Japanese. My nephew is staying with me and we spent a few days in Tokyo. At every station we heard this refrain on the Shinkansen.
As the train left Tokyo Station, and all the other stations on the route:
Shinkansen go-riyou itadakimashite, arigatou gozaimasu.
Thank you for using the Shinkansen.
Shortly before the train stopped at each station:
Shinkansen go-riyou itadakimashite, arigatou gozaimashita.
Thank you for using (=having used) the Shinkansen.