grid limit dispatch for solar plus storage

Dear Sir,
I am working on design and analysis for 150 Mw solar PV plant on DC and due to the grid limitations, it’s AC output is only 60 MW. 
the design include 4 hours storage of capacity 240 Mwh.
the problem that facing me is, when I insert the inputs for the battery storage dispatch model regarding time of charging from grid and times to discharge to the grid, the output didn’t make sense compared to my manual calculations, and that affects severely the financial model net present and IRR, due to the decreased amount of net genration to the grid, although it must be almost the same amount that will be injected to the grid, with or without batteries, and the only thing that will differ is the time of delivery 
kindly advise me
Best Regards 
Rami

Dear Paul,

Kindly find attached my SAM file, beside my manual calculation file : 

note that: 
system capacity = 150 MW- DC 
grid limit = 60 MW - AC 
Battery storage = 240 MWh , and 60 MW power
the system is supposed to generate around 250 TWh - 270 TWh / year, since we have solar irradiance from 1650 - 1800 Kwh/Kwp in Israel and Territories  
if you tracing my excel file for any day in August for example, you can see that the system during the day hour generate and supply the grid directly unless the generation is beyond the 60 MW (grid limit), then the surplus feed in the charging of the batteries and finally in the evening the batteries discharge to the grid.
that didn't match with SAM calculations even I chooses different dispatch criteria to the battery storage, and the affect my financial model and made it in negative.
please can you advise.
and another simple question, if the land of the project is leasing and not purchased, how can I reflect the in the model, ?? added the leasing cost to the  O&M 

Best Regards
Rami