Where did you get this understanding ? Any letter sent by a premed committee or advisor, whether or not it has a cover or evaluation sheet, and regardless of the number of letters attached is considered a SINGLE letter. (see AMCAS definitions below)
So either you are filling :
-committee/letter packet requirement, where you follow the requirements of the UG schools and all materials attached are a SINGLE letter that fulfills virtually every medical school's requirement
OR
-individual letters where you follow the requirements of the medical school.
These two separate categories do not, repeat, do not overlap
Letter Types
AMCAS accepts three different types of letters. Each letter type is equivalent to one letter entry.
- Committee Letter: A letter authored by a pre-health committee or pre-health advisor and intended to represent your institution’s evaluation of you. A Committee Letter may or may not include additional letters written in support of your application. This is sometimes called a Composite Letter.
- Letter Packet: A packet or set of letters assembled and distributed by your institution, often by the institution’s career center. A Letter Packet may include a cover sheet from your pre-health committee or advisor. However, unlike to a Committee Letter, a Letter Packet does not include an evaluative letter from your pre-health committee or advisor.
- Individual Letter: A letter written by, and representing, a single letter author. If you have already included an Individual Letter within either a Committee Letter or a Letter Packet, do not add a separate entry for that letter.