Mr. X is an business man engaged in the business of selling plastic containers in Divisoria. He is very prompt in filing and paying his income taxes, in fact, he pays a month before the deadline just to be sure that he will not incur any additional charges for late payments. However, Mr. X is very stingy as well. He refuse to hire an account to compute for him. One day, a BIR officer went to his stall in Divisoria handing over a Letter of Authority wanting to inspect his books. He confidently handed over his sales record to the said officer. 30 days thereafter, he received another letter from the BIR which contains a Final Assessment Notice (FAN) stating that he is liable for a deficiency income tax. Upon examination of the letter, the BIR stated that Mr. X miscalculated one income item as 1,000 but it should be 10,000 instead and that the basis of the deficiency income tax was merely a mathematical error on the part of Mr. X and so he need not be nervous of any corresponding surcharges so long as he pays such deficiency. Mr X questions this saying that he was denied due process because he did not received any Preliminary assessment notice (PAN) prior to such FAN. Is Mr. X correct? Why or why not. Explain fully and concisely.