High memory use while converting a xlsx file to pdf by Universal Accessibilty (PDF/UA) option enabled

I have a xlsx file with 9 sheets in it and one sheet contains 14000 rows and another sheet contains 6000 rows and rest of the sheet contains less than 200 rows. And each sheet having 20 to 26 columns. The resulting pdf contains around 14000 pages (not enabled whole sheet export).
The problem is, when Universal Accessibilty (PDF/UA) is enabled when converting to pdf , the memory usage is going above 1.1 GB memory and the resulting pdf size is 100 MB (original excel is 3MB), where as If I am disabling the Accessibility option it uses less memory (~400 MB) and the resulting pdf is just 15 MB.
Note that, the excel file contains only the text, no images.
Is this expected with Universal Accessibilty (PDF/UA) is enabled ? Can I do anything better via configuration settings ?