“In RTF output mode PD4ML still uses HTML renderer, developed for PDF output.
It is explained by the link: http://pd4ml.com/cookbook/pdf_page_formatting.htm
That means you get HTML layout of requested width (htmlWidth parameter) mapped to chosen paper format. An actual transformation from dimensions given in screen pixels or in physical units to resulting dimensions on paper is not always obvious.
pd4ml.protectPhysicalUnitDimensions() API call should make dimensions/sizes given in pt, in, cm keept intact.
There some are other support topics address the issue. I.e.
Taken from viewtopic.php?f=3&t=508#p2226