Is the intention that a Monster Slayer must choose between Foundation and Magisterium elementals (as the scroll currently reads) or should the scroll read simply "Elemental"?
This post is to inform you that your question is currently being discussed by the ARC and once some clarification has been made will be posted here. Depending on the level of clarification and discussion (and potential involvement of the Owners or other national staff, if needed) this may take time.
The current Ritual Scroll database is always the final point of reference for scroll text. Thus, as stated on the scroll, either Elemental, Magistarium or Elemental, Foundation must be chosen at the time of the ritual's casting.