(B) the amounts necessary to amortize in equal annual installments (until fully amortized)—
(i) in the case of a plan in existence on January 1, 1974, the unfunded past service liability under the plan on the first day of the first plan year to which this part applies, over a period of 40 plan years,
(ii) in the case of a plan which comes into existence after January 1, 1974, the unfunded past service liability under the plan on the first day of the first plan year to which this part applies, over a period of 30 plan years,
(iii) separately, with respect to each plan year, the net increase (if any) in unfunded past service liability under the plan arising from plan amendments adopted in such year, over a period of 30 plan years,
(iv) separately, with respect to each plan year, the net experience loss (if any) under the plan, over a period of 5 plan years (15 plan years in the case of a multiemployer plan), and
(v) separately, with respect to each plan year, the net loss (if any) resulting from changes in actuarial assumptions used under the plan, over a period of 10 plan years (30 plan years in the case of a multiemployer plan),