I think the big difference in Fischer's arrangements for Tjader and Shearing is that he used them for theme statements and backgrounds for Tjader, but treated them as an independent counterpart for Shearing and thematic material on the Shearing album. Plus, the moods and grooves in the Shearing album are more diversified (program your player to just the Brazilian Tjader tracks - #1, 3, 5, 6, 8, 10, 12 - and you will get the idea).
It's all much more worked out in detail with Shearing, who often weaves his solos around the woodwind parts or is composed into them, while Tjader plays solo over the rhythm section alone, and his theme playing is more or less in unison with the woodwinds, or they play unobtrusive parts behind him. Maybe what the producer asked for. OTOH Tjader was not as good as Shearing in playing written parts.
The tunes by Mexican composer Mario Ruiz Armengol on the Tjader album are a completely different pair of shoes and much more challenging for an arranger. I always listen to the two groups of pieces separately. If you do so, you might appreciate Ardeen de Camp's vocals better.