OCR in DTTG3 - results in files twice the size as original

Firstly - DTTG3 is a much better app than DTTG2.
I have been using the Shortcuts from DTTG3 to automate my capture of magazine pages and making tagged PDF files in DTTG3. So far, so excellent!

I can now OCR the pdf in DTTG3 on my ipad so that I can produce a searchable pdf. However, an A4 sized screen capture of 4 pages that was originally 6MB now becomes 14MB after OCR.
Converting the same pdf to searchable pdf on DT3 on the Mac results in a 6MB final file.
What is happening?
The OCR process on the ipad using DTTG3 is also a lot slower than using Prizmo (for example). I can live with this, but wonder whether I am comparing OCR apples to oranges


Different OCR engines

In that case, probably do the OCR in DT3 as a smart rule

Depending on your needs, that’s a viable alternative.