The OfficeWriter SQL Server Reporting Services integration has two parts:
The server-side OfficeWriter is installed with one of the main OfficeWriter installers (32 or 64 bit). The OfficeWriter Designer and the OfficeWriter Designer .NET have separate installers that can be distributed to end-users.
The OfficeWriter Designer .NET was made available starting in OfficeWriter 8.6. It currently supports 32-bit or 64-bit Excel 2007 and later. To determine which Designer is right for you, refer to OfficeWriter Designer vs OfficeWriter Designer .NET
There were some significant infrastructure changes made for SSRS 2012 in SharePoint integration mode that require a different installation process from native mode.
Server-side OfficeWriter for SSRS 2012 in Native Mode
Perform a custom setup with the OfficeWriter installer to install OfficeWriter for SSRS automatically, or run through the steps to install manually.
Installing for SSRS 2012 with SharePoint Integration
If you are running SSRS 2012 in SharePoint integrated mode against SharePoint 2010 or 2013, there are a separate set of instructions for manual installation.
Original OfficeWriter Designer
Install the original OfficeWriter Designer using the OfficeWriter Designer installer or follow the steps to install the Designer manually. Includes instructions for manually changing the registry keys for the Designer.
OfficeWriter Designer .NET
Install the new OfficeWriter Designer .NET using the OfficeWriter Designer .NET installer.