Fewer tables are included because this is a small sub-category with limited information. The wording of HS Code 9201900053 is “Pianos, incl automatic pianos; harpsichords & other keyboard stringed instruments (excl upright and grand pianos)”, howeover it seems unlikely that this section is mostly harpsichords. More likely, it includes mis-coded pianos.
The assumption is that these are real keyboard instruments and therefore we include them in the ‘Pianos & Keyboards’ Section, but the Category is of limited use. Most of the instruments by far come from China.