No, if you are coming from 4.89 then you don't need to use recovery mode to use HEN.
installing the same version twice was only recommended to use flashwriter. And those models with NAND flash won't allow you to update from XMB when installing the same version number of firmware. Which was why using recovery mode has always been default for that scenario since the day 1 of PS3xploit launch
i mean is there a possibility of releasing 4.90.2 HFW? since 4.90.1 has issues on plug-ins