Difference between AKJ and Damdami Taksal Gurbani ucharan

Waheguru ji ka khalsa, Waheguru ji ki fateh...

Waheguru jee, there is lot of difference in the gurbani ucharan of both of them (AKJ and Taksal)...
Mostly are seen in Jap sahib jee bani and many others bani too.. So which one we should follow???

Please give an example and try to find out what should be correct. Do not make an academic exercise into a point of difference.