No sequence_id increment after fixtures loaded, while setting their ids

If I force id in fixtures (they are autoincremented in model), the sequence is not set correctly in postgresql.

Model :
T_Company:
actAs:
Timestampable: ~
Searchable:
fields: [name]
columns:
company_id:

{ type: integer, notnull: true, autoincrement: true, primary: true }

dn:

{ type: string(255) }

name:

{ type: string(127), notnull: true}

relations:
RssSettings:

{ local: company_id, foreign: rsssettings_id, foreignAlias: CompanySettings, refClass: J_Company_Rsssettings, class: T_RssSettings }

ParentCompany:

{ local: company_id, foreign: parent_company_id, foreignAlias: ChildCompany, refClass: J_Company_Company, class: T_Company }

ParentLinkType:

{ local: company_id, foreign: parent_company_id, refClass: J_Company_Company, class: S_CompanyLinkType }

Fixtures :
T_Company:
A:
company_id: 1
name: A
dn: A
B:
company_id: 2
name: B
dn: B
C:
company_id: 3
name: C
dn: C

Postgresql :
sl3dev=# select * from t__company;
company_id | dn | name | created_at | updated_at
-------------------------------------------------------------------------------------------------------------------------------------------------------
1 | A | A | 2010-05-18 16:55:12 | 2010-05-18 16:55:12
2 | B | B | 2010-05-18 16:55:12 | 2010-05-18 16:55:12
3 | C | C | 2010-05-18 16:55:12 | 2010-05-18 16:55:12

sl3dev=# select nextval('t__company_company_id_seq'::regclass);
nextval
---------
1
(1 ligne)

1 instead of 4 naturally.