Excel chart modification

I have uploaded an excel file in which four charts are formed on the basis of data present in the same file. Data in excel file is changed whenever new chart is required to be formed An Interactive previous close line is to be inserted by means of programming. The previous close line should automatically shift its position whenever new data is entered and new chart is formed. In this chart (due to excel default setting) the gap between high price and upper bound is normal, but the gap between low price (in chart) and lower bound is very high. It is the default setting in excel. But by means of programming the gaps(upper and lower) needs to be kept same. So that the lower bounds don't requires to be changed manually each and every time