CTAS creates 3 x column size if source is 8i 4 x if source is 10g. Why?

CTAS creates 3 x column size if source is 8i 4 x if source is 10g. Why?
CASE1:
local  database etfat: AL32UTF8
remote database eguat: 10g WE8ISO8859P15: nls_length_semantics=char

    desc gua_owner.VGUA_TFA01_BANK_INFO@eguat;

     Name               Null?    Type
     ------------------ -------- ------------------
     BANK_ID            NOT NULL CHAR(6 CHAR)
     OFFICIAL_NAME               VARCHAR2(70 CHAR)
     COUNTRY_NAME                VARCHAR2(42 CHAR)

     create table tim as select * from gua_owner.VGUA_TFA01_BANK_INFO@eguat;

     select char_length, data_length, column_name, data_type from dba_tab_columns
     where table_name ='TIM';
        
    CHAR_LENGTH DATA_LENGTH COLUMN_NAME                    DATA_TYPE
    ----------- ----------- ------------------------------ ------------