Is fasting the White Days based on the solar calendar a correct practice?

Fasting has been singled out by Allah for Himself, and He rewards it without measure. Nothing equals fasting. The supplication of a fasting person is answered, and he has two joys: one when he breaks his fast, and one when he meets his Lord. Fasting intercedes for its companion on the Day of Judgment, and the bad breath of a fasting person is more pleasing to Allah than the scent of musk. Fasting is a shield and a fortress against the Fire. Whoever fasts one day for the sake of Allah, Allah will distance his face from the Fire by seventy autumns. And whoever fasts one day seeking the countenance of Allah will enter Paradise. There is a gate in Paradise called Ar-Rayyan through which only those who fast will enter. Voluntary fasting compensates for any deficiency in obligatory fasting, such as 'Ashura, 'Arafah, the White Days, Mondays and Thursdays, and six days of Shawwal. The White Days are the thirteenth, fourteenth, and fifteenth of every lunar month, and acts of worship are based on the lunar months.