which would explain the last letters signifia of these models,
Satellite L745-SP4256CL (CL) <-, l845-SP4202KL (KL) <-.
Because the satellite equipment offered in the U.S. do not carry those last two letters at the end Satellite L755-S5153 <-
Because the satellite teams in europe so what are the denomination Satellite L870 <-
You cannot compare notebooks model name or model numbers between notebooks designed and offered in US, Asia or EMEA (Europe – Middle East – Nord Africa).
Every continent has own market and attributes. I’m not expert for this stuff but I presume Satellite L745-SP4256CL is not for US market but Satellite L755-S5153 is definitely offered on US market.
Notebooks are country specific products and depending on the market they have different label or notebook name.