D1 and Oracle numeric data types

We have following problem.
Our Oracle table contains decimal(10,2) field.
(decimal(X,Y) or number(x,y) make the same problem).

We have found, that there exist some "magic" numbers (0.94 for example),
witch when are stored in the table make this spell:
Deleting or updating record from IDAPI client is more not possible.
When we try it we can see message "another user change the record"

Known facts:
 Update mode of TTable component is "where all". We can't use "where key
 16-bit Database Desktop work the same way. (It seems problem is in
idapi or in SQl link)
 It seems that IDAPI/SQL link produces some uncertainty while converting
floating point data types.

 Did you meet the similar problem?
 Did you solve it?
 Can you help us?

Please, send your comment to my e-mail address.
Any help will be appreciated.