Possible bug: amount in Annual income bucket

[sdz]

Hi,

I am a new user of MoneyWell and I am very pleased with this app.
Actually, this is the first shareware that I bought since switching
to Mac! (thanks to Alan for pointing out this great app in his blog)

I have found a strange behaviour when creating a new income bucket. I
haven' t found it mentioned in previous postings to this list (but I
haven't searched that well though).

1. create a new income bucket.
2. set the frequency to annually.
3. set the amount to 2500, the value is changed to 2,499.96.

The same strange behaviour arise for other values. 1256 -> 1,256.04;
etc.

I guess it may stem from some rounding issues.

Silvano

[Kevin Hoctor]

Hi Silvano,

Welcome to the Mac (and thanks Alan for pointing him to MoneyWell).

Yes it does and I'm working on a fix for that. The average is based on
a monthly amount and rounding to displayed decimals is causing this
error. It will change in a future release.

Peace,

Kevin Hoctor
ke...@nothirst.com
No Thirst Software LLC
http://nothirst.com
http://kevinhoctor.blogspot.com

[Alan Schmitt]

On 23 avr. 08, at 14:07, sdz wrote:

> 1. create a new income bucket.
> 2. set the frequency to annually.
> 3. set the amount to 2500, the value is changed to 2,499.96.
>
> The same strange behaviour arise for other values. 1256 -> 1,256.04;

This is very probably a rounding error:
2500 / 12 = 208.3333333....
208.33 * 12 = 2499.96

1256 / 12 = 104.66666666....
104.67 * 12 = 1256.04

Alan

[Blair Watkinson]

It is due to rounding, but "error" may not be the right word...

If a person wants to allocate 2500, somehow that has to get into the
buckets in discreet, whole-cent amounts. There is no way to do it
with an equal amount every month. MoneyWell rounds to put the money
into buckets. It could randomly assign months to put in a few extra
cents. Or it could provide an interface for you to specify those
months.

More reasonably, though, would be to select an amount that is
divisible by 12. I think that generally this is what people would do
if they were using actual physical envelopes, rather than cyber-
buckets... they'd put in the same discrete amount every month to hit a
target that is somewhere close to what the yearly total would need to
be.

So, I'd recommend starting with a number divisible by 12 for the
purpose allocating money... $2400, or if it needs to be close to 2500,
you could pick 2499.96 or 2496 or 2500.08 or 2502, etc. Using an
amount divisible by 12, you should be able to get within 6 cents of
any target amount.

Blair

[Alan Schmitt]

On 23 avr. 08, at 15:38, Blair Watkinson wrote:

> More reasonably, though, would be to select an amount that is
> divisible by 12. I think that generally this is what people would do
> if they were using actual physical envelopes, rather than cyber-
> buckets... they'd put in the same discrete amount every month to hit a
> target that is somewhere close to what the yearly total would need to
> be.
>
> So, I'd recommend starting with a number divisible by 12 for the
> purpose allocating money... $2400, or if it needs to be close to 2500,
> you could pick 2499.96 or 2496 or 2500.08 or 2502, etc. Using an
> amount divisible by 12, you should be able to get within 6 cents of
> any target amount.

Yes, this is a very nice suggestion. Since this amount is for
planning, a few cents error won't matter.

In fact, thinking a little more about it, it seems that the purpose of
this income amount only matters to make sure the spending plan is not
in the red. It has no influence when allocating income (which seems to
be based on the expense buckets).

Alan

[Blair Watkinson]

You know, I actually missed that this was an income bucket...

The same effect occurs for expenses if you plan them yearly also. I
generally have avoided this artifact because I do all my planning at
the monthly level, including my income.