Created attachment 82799 [details]
Test Kit

Currently all date (and time) data in a sheet imported from an other document will show wrong values if source and target document have different date base settings in menu 'Tools -> Options -> Calc -> Calculate - Date'.

Steps how to reproduce Reproducible with server installation of "AOO 4.1.0-Dev – English UI / German locale - [AOO410m1(Build:9750) - Rev. 1565724 - 2014-02-09]" on German WIN7 Home Premium (64bit)", own separate user profile:

1. Download and unzip attached test kit
2. From AOO Start Center open "TargetTest_DateBase is 31.12.1899.ods"
3. Menu 'Insert -> Sheet from File -> Source__Date Base is 1.1.1904.ods
  [Insert] - Tabelle1 [ok]' 
4. In new sheet check value shown in A1.. Should be 1.1.2014, is 31.12.09

The root of the problem is that differences in  "table:null-date" parameter (ODF 1.2 Part 1: OpenDocument Schema 9.4.2 <table:null-date>) of both documents are not considered during sheet import.  

The enhancement request is that contents in all cells with a date or time format containing a number value (not formula) should be corrected by adding difference:
(source-document table:null-date) - (target-document table:null-date)

Additional info:
----------------
(a) A problem would be standard number values what will be used as date
    in other cells with a reference:
    A2 contains Number "40178"
    A3 Contains formula "=A2" and is in date format
    this can not be recognized with acceptable costs and so there is no
    way to correct that.
(b) There might be other snares like (a)
(c) in a second step a similar adaption should be done for import from 
    not-ODF-documents
(d) This one is a spin off from "Bug 95710 - Date object pasted from another 
    workbook sheet with different date base changes value"
(e) Also a solution for copy / paste between documents with different 
    date base needs enhancement
(f) DDE-reference-link works fine
(g) "='file:// .................." reference also needs a solution 
    as requested here