Revision on my english, thanks

If some would be kind and review this text for gramatical erros or any comments about my english. thanks.

Can a compay change from variable Cost to absorption Cost with in a year ?

Why accounting has to complicate everything? On inventaries FIFO seems the more obviously used(clear out the first inventory), but it is not, LIFO is the one (in USA). On depreciation again the straight-line (equal amount of deprectiation will be taken each period) seems quite right, but we could do Double Declining Balance Method; now for finding the price per unit we could use absorption Costing, but variable costing is well used for managers.

Lifo could lead us on misinterpretations with the inventory values, because the inventory is outdated.

Using absorption costing, the operating income could fluctuated not for sales but for changes on inventory.

Then is LIFO and Absorption Costing a good couple?