Calculating monthly costs

[Confusi]

I have a file with the following entries:

Frequency - NRC - MRC - Start Date – End Date<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
(1) One-off - $200 - $0 - 4/5/2011 - 4/5/2011<o></o>
(2) Monthly - $0 - $500 - 12/4/2010 - 6/3/2011<o></o>
(3) Monthly - $0 - $200 - 4/1/2011 - 6/30/2011<o></o>
(4) Quarterly - $0 - $300 - 12/1/2010 - 2/28/2011 <o></o>
(5) Quarterly - $0 - $600 - 2/25/2011 - 5/24/2011<o></o>
<o> </o>
My desired result for the Jan 2011 to Dec 2011 columns would :<o></o>
<o> </o>
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec<o></o>
(1) April is 200 while all the rest is 0.<o></o>
(2) Jan to May is 500 while Jun is 50. All the rest is 0.<o></o>
(3) Apr to Jun is 200 while the rest is 0.<o></o>
(4) Jan to Feb is 100 while the rest is 0.<o></o>
(5) Feb is 50, Mar and Apr is 200, May is 150, the rest is 0.<o></o>
<o> </o>
I still have Half-year and Yearly entries but they follow similar logic.<o></o>
<o> </o>
I can’t seem to find the best way to do this. Should I segregate the frequency first before doing the checking? But bec this is a moving file (being updated monthly) I’d like a formula that can catch all. Please help! Thanks!<o></o>

 

[Confusi]

I was thinking abt this the whole night, maybe I should do a Jan to Dec columns to temporarily store the result of the month (say check if Jan is within the Start and End range) and then check if it's full month or not, then store the no. of days. At the final result field, use hard coded no of days month to calculate the days.

Does this make sense?