Google API v1.3, mismatch in total traffic API vs Adwords keyword tool

Why such a huge difference?

[AjiNIMC]

I see there is huge difference between API traffic estimation and Adwords keyword tool traffic estimation: (Both of it is exact search)

1) Through Adwords API

Array
(
[0] => AdWordKeywordVariation Object
(
[_row] => Array
(
[text] => blue widget
[language] => en
[advertiserCompetitionScale] => 5
[avgSearchVolume] => 1220000
[lastMonthSearchVolume] => 673000
)

)

[1] => AdWordKeywordVariation Object
(
[_row] => Array
(
[text] => red widget
[language] => en
[advertiserCompetitionScale] => 5
[avgSearchVolume] => 135000
[lastMonthSearchVolume] => 165000
)

)

[2] => AdWordKeywordVariation Object
(
[_row] => Array
(
[text] => green widget
[language] => en
[advertiserCompetitionScale] => 4
[avgSearchVolume] => 2900
[lastMonthSearchVolume] => 5400
)

)

2) Through [adwords.google.com...]

* [blue widget] - 201,000 (Last month, Nov) - 301,000 (average)
* [red widget] - 40,500 (Last month, Nov)- 27,100 (average)
* [green widget] - 140 (Last month, Nov) - 140(average)

Now if you see the difference is

* Avg (1220000 - 301,000) ...Last month(673000 - 201,000)
* Avg (135000 - 27,100) ... Last month (165000 - 40,500)
* Avg (2900 - 140) .... Last month (540 - 140)

Why such a huge difference?

Thanks,
Aji

[AjiNIMC]

Looks like the API supports only the broad matches for traffic estimation, the exact matches are not matching at all. Whereas the broad matches are somewhat closer.