http://office.microsoft.com/en-001/excel-help/subtotal-function-HP010062463.aspx
there's serveal function number user can use, for example "103 COUNTA"

Currently, I tried (9 MAX) and (4 SUM), it works fine. BTW, with (103 COUNTA), I got

org.zkoss.poi.ss.formula.eval.NotImplementedException: SUBTOTAL - with 'exclude hidden values' option
at org.zkoss.poi.ss.formula.functions.Subtotal.findFunction(Subtotal.java:77)
at org.zkoss.poi.ss.formula.functions.Subtotal.evaluate(Subtotal.java:92)
at org.zkoss.poi.ss.formula.OperationEvaluatorFactory.evaluate(OperationEvaluatorFactory.java:132)
at org.zkoss.poi.ss.formula.WorkbookEvaluator.evaluateFormula(WorkbookEvaluator.java:539)
at org.zkoss.poi.ss.formula.WorkbookEvaluator.evaluateAny(WorkbookEvaluator.java:316)
at org.zkoss.poi.ss.formula.WorkbookEvaluator.evaluate(WorkbookEvaluator.java:255)
at org.zkoss.poi.xssf.usermodel.XSSFFormulaEvaluator.evaluateFormulaCellValue(XSSFFormulaEvaluator.java:266)
at org.zkoss.poi.xssf.usermodel.XSSFFormulaEvaluator.evaluate(XSSFFormulaEvaluator.java:119)
at org.zkoss.zss.model.impl.BookHelper.evaluate(BookHelper.java:471)
at org.zkoss.zss.model.impl.BookHelper.getFormatText(BookHelper.java:1013)
at org.zkoss.zss.model.impl.RangeImpl.getFormatText(RangeImpl.java:271)
at org.zkoss.zss.ui.impl.Utils.getFormatText(Utils.java:915)
at org.zkoss.zss.ui.impl.CellFormatHelper.getHtmlStyle(CellFormatHelper.java:89)
at org.zkoss.zss.ui.Spreadsheet$ExtraCtrl.getCellAttr(Spreadsheet.java:3032)
at org.zkoss.zss.ui.Spreadsheet$ExtraCtrl.getRangeAttrs(Spreadsheet.java:2878)
at org.zkoss.zss.ui.Spreadsheet.renderProperties(Spreadsheet.java:1647)