In periods of rising costs, LIFO will produce the greatest cost of goods sold, thus the lowest net income and FIFO will have the opposite effect. In terms of fairness, not accounting, actual cost for inventories that are bought by the unit and average cost for bulk inventory will produce the most accurate cost and net income numbers. There was a time when doing it manually would have made actual cost very difficult but computers have greatly simplified the process.
What is fair most often is followed by the question, "to whom?" In my view, factual accuracy always trumps an opinion of what is fair.