USA Adjusting prior year mis-steps on current year tax return

[Angie]

I have a client who keeps their own books (cash method). 2015 is the first year that I'm preparing their return (Partnership, Form 1065.) In both 2013 and 2014, they recorded errors on their books (expenses were accidentally recorded as assets). Their previous accountant did not catch the errors, and both 2013 and 2014's tax returns do not take advantage of the expenses.

Am I OK to simply record the corrections and take the expenses in 2015? The expenses in question are about 3% of overall expenses for the year. Do I need to note anywhere on the 1065 that I am claiming prior year expenses?