This sequence, BTE SERCYV, stands for Bachillerato TÉcnico de SERvicios: FIP Contabilidad Y Ventas.

(FIP stands for Figura Profesional, which I think you might translate as Professional Profile.)

In other words, it means the same as "COMERCIALIZACION Y VENTAS", which you say figures as the FIP in the following year; it's just an abbreviation of the same thing. It would surprising if the FIP were different, since the Bachillerato speciality is a three-year course and you wouldn't normally expect people to change course from one year to the next.

So it's a Bachillerato (which for the US I think you can safely call a High School Diploma), specifically a Bachillerato Técnico (as opposed to a Bachillerato en ciencias or Bachillerato General Unificado), and in the general area of Servicios (as opposed to Agropecuaria, Deportiva, Industrial, etc.), and within that area it's specifically the FIP in Comercialización y Ventas (as opposed to Accountancy and Administration, for example).

Here's a list of bachilleratos offered at a particular school:

"Los alumnos que asisten a este plantel educativo, pueden optar por diferentes especialidades académicas como Bachillerato General Unificado en Ciencias; Bachillerato Técnico de Servicios FIP, Comercialización y Ventas; Bachillerato Técnico de Servicios FIP Contabilidad y Administración; Bachillerato Técnico Industrial FIP Instalaciones, Equipos y Máquinas; y Bachillerato Internacional."
https://educacion.gob.ec/gobierno-entrega-la-repotenciacion-...

See also
https://www.proz.com/kudoz/spanish-to-english/education-peda...
https://www.proz.com/kudoz/spanish-to-english/certificates-d...