h12 = 29 representing the day of the month that I need the value of
G12 to be added to the total in m12.
h13 = 15 representing the day of the month that I need the value of
G13 to be added to the total in m13

a12 = Microsoft

o12 = the market value of my microsoft shares.
n12 = the current price of each share.
g12 = $1000 (the amount of money I invest into Microsoft each
month ... always the same monthly investment)
h