Continuous line bar chart

I understand that it is quite hard to answer with the little information provided. I will try to make it a little more clear.

Let's say I have a company and I sell bicycles. Another company is a customer of yours and buys bikes to sell them at their store. They tell you that they will buy 5 bikes per month (to get some discount for example). I want to see with a barchart and my data if they are following their promise. The data I have is sale per invoice.

So this is the table:

So now my barchart has a bar per month and a line at 5 bike sales. Some bars are above the line and some beneath the line. However, because there are missing rows, PowerBI does not know the prognosis value for that month so there is a gap between the line between months (see graphs in first post). I know that a solution is to add custom rows for missing months with 0 or 0,01 bike sales and 5 as monthly prognosis, but as I got a lot of companies and also a lot of missing months I do not see that as a good solution. To add up to that, I could not find the function to add custom rows to an existing table.

Could you provide me another solution please? Thanks for your first answer but I do not think that is what I meant, maybe with this it makes it more clear.

Thanks in advance!

Thijs

Dear Greg_Deckler, could you please look at my response with the more in detail explanation of my answer and let me know if you still cannot help me, thanks!