This may not be *strictly* what you were asking for, but hopefully it's *better*.

The result just after `Tab` has been pressed after typing `2.5`

in the `Hours used:`

column can be seen in this screenshot:

The worksheet is to be set up as follows:

Enter `8`

in `B5`

(or use whatever formula you do to calculate the value)

Enter the following formula in `B6`

and ctrl-enter/copy-paste/fill-down the rest of the column as required:

```
=H5
```

Enter the following formula in column `H`

where appropriate:

```
=IF(ISBLANK(D:D),"",B:B-D:D)
```

Note that an entire column reference can be used instead of the specific cell reference to refer to cells in the same row as the formula itself. (The "normal' formula would, of course, be `=IF(ISBLANK(D5),"",B5-D5)`

entered in `H5`

.)

As you can see, this enhanced solution pre-fills the next cell of the `Banked hours:`

column with the amount of remaining hours.

In fact, the whole table can be improved by removing the `Remaining hours`

column entirely:

Enter the following formula in `B6`

and ctrl-enter/copy-paste/fill-down the rest of the column as required:

```
=IF(ISBLANK(D5),"",B5-D5)
```

This formula refers to the cells in the *previous* row rather than the current one.

**Notes:**

`ISBLANK(D5)`

is equivalent to `D5=""`

*provided* `D5`

*doesn't contain a formula*. For the case of a formula, only `=""`

works correctly. `ISBLANK()`

will always return `FALSE`

even if the formula evaluates to `""`

thus showing a "blank" cell.