Something strange with mana regeneration

Hi all. playn druid on lordaeron and met a problem had 101 Mana regeneration per 5 sec after I lvlup I have 100. same I had with few last lvls. cant understand why please help. when I lvlup in chat yellow letters about +2 spirit but mana regen falling... Sory for my bad English =/

spirit is not same as mana regeneration (+2 spirit is not +2 mp5)

as you level, your base stats go up (+2 spirit for level), but the amount of spirit for 1 mp5 also goes up