I copied this text from the website of the Dutch Tax-administration:
1e Supplies/services taxed at 0% or not taxed at your level Enter the turnover for goods and services supplied by you in the Netherlands at 0% or for which you are not taxed applies to goods and services in the Netherlands to which the 0% rate applies (see table II). Also enter the turnover for which the VAT has been cross-charged to your customer. This is the case if your business is not based in the Netherlands and you supply goods or services within the Netherlands to a business based in the Netherlands.
So line 1e shouldn’t show net difference between sales and purchases. It has to show only the net sales figure.
As I Into the Mirror already stated when it is an inland purchase we only have to report the tax paid, not the purchase value. Exemption to this rule are the products delivered and services rendered to the business coming from within the EU and from outside the EU. The net purchases are reported at line 4a and 4b