They are just doing that because the price has not reached the softcap yet. The moment it hits the target, they will halt the sale.
No, as for the Ubex the softcap has been reached which is about 4000 Ethereums, most surprising all the coins have been sold just by in one day. Now their target is reaching the hardcap I think it's normal when they have to extend their ICO in order to make it success and that's not a big deal for me as long as the project can be successful. Every project have their own strategy some of them might end their sales after reaching the softcap, some might be waiting until they hit the hardcap target.