Your description of the stroller says from birth to 15kg. I'm looking at it on the Smyths Toys website as interested in buying and it says from birth to 22kg. This is quite important in my decision making to keen to know which weight is correct?
Every country has different laws and requirements. When introduced to the market, the Litetrax line was, indeed, up to 15 kg - it may be that in your country, the brand did extra weight testing to be able to claim the load capacity of up to 22 kg. However, I must warn you that a 22 kg (a 5-6 years old) will be very, very tight in the seat that is not as long on this pushchair. Also good to know is that most up-to-15-kg strollers of an OK quality can actually handle more than that - the problem is more the room inside than the weight maximum.