Need help typing a Portugal coin

I need help identifying this Portugal coin. It is silver, 17 mm in size and weighs 1.28 grams. 

It looks most like the KM 238 but that coin is larger (22 mm) and weighs more (3.06 g).  So that can’t be what I have. 

N#35497
 

Its size and weight most closely resembles the KM 236 (17 mm and 1.53g) but it has a “4” flanking both sides of the base of the crown. My coin has rosettes flanking the base. 
N#35454
 

So is my coin a subtype of KM236 or is it altogether a type not yet catalogued in Numista?

Thanks in advance for sharing your expertise. 

I think that the two flanking ‘4’ are not ‘4’, but rosettes instead. The main images on the ½ Tostão page have horrible quality, but if you check the examples/past sales at the bottom of the page, there is a much better example.

SGreg85

I think that the two flanking ‘4’ are not ‘4’, but rosettes instead. The main images on the ½ Tostão page have horrible quality, but if you check the examples/past sales at the bottom of the page, there is a much better example.

 

I think you are absolutely correct. I didn’t pick up on that at all. Thank you for your reply. 

Correct. KM# 236.1 JOSEPHUS

KM# 236.2 IOSEPHUS

Thanks to all for the various suggestions.

To my eyes, it is difficult to say of the objects flanking the crown are rosettes or crosslets.  But they are not 4s.  

Suggested modifications have been made.

Maybe change the title too? 40 reis.

As I understand, KM is wrong on this.  

There is an explanation in the Comment section, and all the Portuguese auction houses list this as a ½ tostao / 50 reis coin.

I saw the explanation about the 1688 law after I posted but figured maybe Krause knew more than I did since they do list others with XXXX as 50 reis.