POI was making a mistake of using evaluateAllFormulaCells for evaluation value of cell containing formula with LOOKUP function. For cells that contain the formulas, their formulas are evaluated, and the results are saved. In output file, although these cells remain as formula cells, their value isn't correct (e.g. cell E45, E46 in sheet 'Generator' of attached testcase) You can get data spreadsheet for test-case.
Created attachment 22765 [details] one added test spreadsheet file
Created attachment 22770 [details] Test-case spreadsheet in case formula cell containing function VALUE
More information, in case spreadsheet uses function VALUE, HSSFFormulaEvaluator doesn't update value in the cell. Attached file for test-case data.
Implementation for VALUE() added in svn r708262. I've made an assumption that this is all that needed to be fixed for this bug. Please reopen with more details if you still have problems.