OP asked if the “academic levels” are similar at Andover and Deerfield.
Both are outstanding schools with respect to academics.
An important differentiating factor to consider between or among various prep schools is the school culture.
Andover has a reputation for having a fairly intense academic atmosphere with a substantial workload while Deerfield is well known for a culture focused on both sports and academics.
How will your child respond to a highly competitive academic atmosphere ?
The acronym schools all offer superior academic environments, but some school cultures are more competitive than others.