How to customize summary information in dashboard

I have created a country wise crosstab dashboard with 2 measure values where one measure value is picking up the maximum value on database for considering at month level (for eg: if there are 100 rows of data for a column in particular month is available then only the maximum value within those 100 rows of data should by pick it up by that measure column as per below).

Measure A

20

30

40

--

--

90

15

10 (100th row)

Result of measure A = 90

In above case the value of measure A should be display on dashboard is 90 which si the maximum value.

However the 2nd measure is just showing the summation of all values in a month.

for Eg the value of 2nd measure will be as per below for a month:-

Measure B

10

20

30

40

50

60

70

05

Result of Measure B = 285 (i.e the sum of all values)

Now, the problem is happening while creating a dashboard, the summary data at the bottom automatically created is also showing the maximum value for 1st measure at summary level instead of total sum as per below.

Month Measure A Measure B

Jan 90 286

Feb 30 100

Mar 65 300

Summary 90 686

Therefore, please can me include some feature by which we could customize the summary data as per the requirement in dashboard will be really helpful.

Based on above implementation , lot of summary releated issues on dashbaord will be resolved for amny customer.