PnL with FIFO and LIFO

I have the following trades:

Sequence Side Quantity @ Price1.       Buy    12     @ 1002.       Buy    17     @ 993.       Buy    3      @ 1034.       Sell   9      @ 1015.       Sell   4      @ 105with sold quantity = 9+4 = 13and current position size = (12+17+3)-13 = 19and markPrice = 99

I want to calculate the netPnL, realizedPnl and unrealizedPnl by using the most precise valuation type. I only know 3 valuation types: FIFO, LIFO, WAC. I did not choose WAC because it is not precise enough. So I want to choose either FIFO or LIFO. Here the calculations:

FIFO:

realizedPnL = (9*101 + 4*105) - (12*100 + 1*99) = +30unrealizedPnL = 19*99 - (16*99 + 3*103) = -12netPnL = 30 + (-12) = 18

LIFO:

realizedPnL = (9*101 + 4*105) - (3*103 + 10*100) = +20unrealizedPnL = 19*99 - (7*99 + 12*100) = -12netPnL = 20 + (-12) = 8

Now my questions:

1. Are the calculations right? I thought that the netPnl must be always the same - regardless of the valuation type. But this is not the case here. Why?
2. Which is more precise? FIFO or LIFO? Which should I use?
3. Is there any other valuation type which is more precise than FIFO or LIFO? I need the most accurate valuation type.

EDIT:

The error was within the LIFO calculation:

Instead of

realizedPnL = (9*101 + 4*105) - (3*103 + 10*100) = +20

this must be used:

realized PnL = (9*101 + 4*105) - (3*103 + 10*99) = +30