I was going to ask the same question, now that the RUT240 is officially going into an EOL phase and I have to select my replacement for the future. The website is indeed not very helpfull.
You say the LTE module is different, I believe you ofcourse. But what exactly does this mean? Is there a speed difference? Is there a difference in available bands?
Now that the RUT240 is officially EOL it would be better to update the website to reflect the differences better I guess. It's weird one model is replaced by two, with no differences between them according to the official website.