Originally Posted by toddos
To be 100% correct, it's an Adobe Digital Editions rendering engine issue with the versions that Sony used for its older (pre-350/650/950) readers. Sony could upgrade the older models but they'd rather you upgrade to a newer model. Alternatively you could install alternate software but that may bring other issues like needing to liberate DRMed books that otherwise would've worked on the stock firmware.
Actually, the 900 supported justification in ePub and without the argin page numbers.