Of course, it is entirely up to you which package you feel benefits you the most, so do what you feel is best for you.
Financially, where you are putting through £1,000 or more every month it would benefit you to move across to the standard package. Similarly, if you are putting around 10 or more agreements through every month, it will be financially beneficial to you to move from the basic to standard option.
Here is an example:
One month you put through 10 agreements for £1,000 each.
On the basic package (No system fee; £4.00 per Agreement; 8% commission):
Commission = £800.00
Agreement fee @£4.00 per agreement = £40.00
Monthly fee = £0.00
Total payment to you = £9,160.00
On the standard package (£10.00 system fee; no charge per agreement; 5% commission):
Commission = £500.00
Agreement fee = £0.00
Monthly fee = £10.00
Total payment to you = £9,490.00
So, in this case you would have increased your payment by £330.00 by switching to the standard option.