a statement is simply a sentence that is a claim or is tmaking a point, there are many different types of statements.
statements can describe a wide variety of aspects, be it physical or non physical, the conclusion and the validity of the statement depends on what is being discussed and the context, it also has to be analyzed in order to determine wether it's true or false , statements themselves dont change anything, they just describe the feats shown within the series,so when used by themselves dont determine if something is true or false, they only determine whether something is true or false if the statement is based on something physical that is true within the series and has evidence directly or indirectly from that physical thing.
most characters aren't all knowing about everything, even characters who are knowledgeable about a certain subject can lie, they may not know everything about that subject or can simply be misinformed, sp their statement has to be shown to be true or is possible compared to what the subject is
for example: In the manga, political leaders state that yujiro is as strong as nuclear war heads
sure he said that, but does he know what he is talking about? did he ever drop a nuke on yujiro and he managed to simply tank it? is the information provided accurate and not simply a byproduct of his fear? Does he know everything about yujiro's abilities and strenght? there are other questions to be answered as well.
even if a the statements provided aren't contradicted that doesnt automatically mean the information is right. statements can be wrong or right no matter if its contradicted or not,all the characters do within the fictional setting is provide the information/statements, its up for the us to see if what is being said is true or possible based on the feats seen in the story and then analyze the info provided based on the context.
there are also Guidebook statements, and people generally just take them at face value
however, guidebooks are just supplemental information that expands upon feats from a fictional work, If it's information is contradicted by the fictional work it's describing or isn't backed up by any evidence then its most likely false.
for example, if a guidebook describes a character's attack potency to be 5B but he consistenly shows 7C feats, then the guidebook statement will be ignored
This is why statements that are describing physical phenomenons like AP, speed etc have to be analyzed on a step by step basis. The feats are what shows the physical changes that occur and the statements are just conclusions that can be true or false, so they should not be taken as evidence for feats