I am having issues getting a hold of amplitude measurements using c.phone.A1.column_name('A1') (...A2, A3) when extracting vowel points. I have tried enriching with both analyze_vowel_points and analyze_vowel_points_refinement. I am able to extract formants and bandwidth from both these enrichment types (tried via resetting database and re-enriching with each). The source code indicates I should be able to extract amplitude, could this be a bug?