[maddermax]

I don't have the book to hand, but it states that lances switch to Hand Weapon. If it states it's a Lance with the Deathpiercer rule, then it grants KB on the charge. If it states it's a Lance, and grants the Bearer Killing Blow, then it grants NB even with the HW.

I've had this come up before.
Magical weapons = always use, cannot switch to another weapon.
Lances = Always switch to hand weapon.

So, there is no answer, except for Bretonnians who always use the lance of course, due to their special rule. Meanwhile, while I agree with you on the +2 in all phases by RAW, but you'll note that Bretonnian magical Lances all specify "+2 str. on the charge" only.

 

[maddermax]

brets are not the only army with magic lances though

Indeed, though my answer on the first page is relevant here. There is no answer. One rule says "always use magical weapon", the lance rule say you "must change to hand weapon" after the charge. A magic lance is bound by both rules, and so, until GW gets off their asses and does something, it will remain unanswered.

Best bet is to play it like it was in 7th - use the magical lance all the time. Why they bothered changing the lance rule, of all things, I don't know.