Can I integrate 2 form to use a single google spreadsheet

If I have google spreadsheet integration set up with my original form, will my cloned form automatically write to the same spreadsheet?  Is it possible for both forms to write to the same document?

No, it is not possible to integrate 2 different forms to use the same spreadsheet. This will break the integration and neither will work. You will need to have them use to different spreadsheet and us some formulas to copy and all the data of both spreadsheets and paste it in another (third) spreadsheet.

I haven't tried this but looks possible using this method ?

http://www.jessespevack.com/systems-leadership/2015/4/22/pulling-spreadsheet-data-no-scripts-required

I'm pretty sure it is possible to combine data from multiple spreadsheet but, as my colleague previously mentioned, having two different forms passing data automatically to the same sheet is not possible because, each integration will create its own sheet to pass its own data.

You could always try to create another spreadsheet and use some Script to pass the data from the two forms to the new one.