sfas 115 requires the use of amortization schedules for AFS and HTM securities in the same form as with bond amortization schedules.

If trading security mark to fmv each period, report on b/s at fmv and unrealized holding gain/loss to income statement under other revenues and gains or other expenses and losses.

If AFS security, amortize like a bond investment. each period compare c/v investment to fmv of investment, and report on b/s at fmv and take unrealized holding gain/loss to other comprehensive income which closes to accumulated other comprehensive income.

If held to maturity, report on b/s at cost and amortize like a bond investment with no gains or losses recognized unless sold.

If Sfas 159 is elected then:

#1 it is irrevocable and you are stuck with it.

#2 all securities- trading, AFS, and htm go to b/s at purchase date at fmv and mark up or down each period to fmv and report at fmv on b/s with unrealized holding gain/loss to income statement under other revenues and gains or other expenses and losses.

which part is confusing you?