Grid spread allocates data across the cells on the webform and runs on the client browser.Mass allocate triggers a calc script which can allocate data beyond cells those are available in the form.
If your administrator has enabled Grid Spread as a data form property, you can specify an amount or percentage by which Planning increases or decreases values across multiple dimensions on the data form, based on the existing values in the target cells. You immediately see the result in the data form and can save the new data or discard it. When calculating the spread data, Planning ignores read-only and locked cells and cells having supporting detail. Data integrity is ensured by spreading values only to cells to which you have access.
If you have the Mass Allocate role (assigned in Oracle's Hyperion® Shared Services) and an administrator has enabled Mass Allocate as the data form property, you can spread data using the powerful feature, Mass Allocate, which:
Allocates data to all the source cell's descendants
Allocates across multiple dimensions
Spreads data even to cells not displayed on the data form
Does not require that you have access to the target cells
Cannot be undone after you mass allocate values
Is processed with dynamically-created calc scripts
Executes the calc scripts against the Essbase server, against all dimension combinations
Can use customized spreading patterns, created by an administrator (see the Oracle Hyperion Planning Administrator’s Online Help)