Hello,
The "per unit" is just a translation text which is displayed.
You can use the translation override to not display that text.
You can also use a view override to change the logic in order to display a different translations depending the product.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.